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1
Khan, Zulfiqar Ali. "Novel iodine mediated carbocyclisations and hypervalent iodine(III) reagents." Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/54137/.
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The first chapter focuses on the introduction of iodine mediated carbocyclisations and their applications continue to present a stimulating challenge in target- and diversity-oriented synthesis. The second chapter discusses applications and brief literature overview about classical approaches towards the syntheses of indene derivatives. Herein the syntheses of 3-iodo-1 H-indene derivatives via iodonium-promoted 5-endo-dig carbocyclisation of 2-substituted ethynylmalonates as a key starting material are described. Within this study, we were able to show that the 3-iodo-1 H-indene can be used as a synthetic platform not only for the palladium chemistry but also as a catalyst for the in situ generation of [text unavailable] hypervalent iodine reagent. Additionally, 3-iodo-1 H-indene derivatives have the potential to perform asymmetric synthesis. Third chapter demonstrates tandem iodine mediated carboannulation of the stilbene malonate derivatives via either 5-exo- or 6-endo-trig mode under basic reagents with subsequent lactonisation to structurally complex indanes and tetrahydronaphthalenes with three new stereogenic centres. In the present study, a unique stereochemistry was observed in the case of tetrahydroindenofuranones and confirmed by single crystal X-ray analysis. These cyclisations proceed exclusively with the retention of configuration to form tetrahydroindenofuranones. Both the compounds formed as a single diastereomers as judged from their 1H and 13C NMR spectrum. In fourth chapter the synthesis of novel simplified analogues of IBA by oxidation of [text unavailable] diiodoacrylic acids are described. Additionally, the ligand exchange resulted in tosylate derivative. The new reagents have been utilized in various well established oxidative transformations with superior or similar reactivity as conventional hypervalent iodine(III) reagents.
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Jia, Zhiyu. "Transformations promoted by the hypervalent iodine reagents." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/134832.
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Malmedy, Florence. "Stereoselective transformations using chiral hypervalent iodine reagents." Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/93576/.
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Hypervalent iodine (III) compounds are efficient, selective and environmentally friendly reagents. Due to their electrophilic nature and excellent leaving group ability, they can be used to mediate oxidative transformations; for example, the oxidation of sulfides to sulfoxides, the α-functionalisation of ketones, the dearomatisation of phenols, the functionalisation of alkenes and, more recently, the rearrangement of various substrates. In this thesis, the stereoselective rearrangement of propiophenone derivatives mediated by chiral hypervalent iodine reagents is described (Scheme i). A chiral lactate-based iodine (III) reagent was used to synthesise 2-arylpropionate derivatives with moderate to good yields and enantioselectivities. These compounds are highly attractive as they are direct precursors to Non-Steroidal Anti Inflammatory Drugs (NSAIDs). Scheme i. Rearrangement of propiophenone derivatives to 2-aryl-propionates. The cyclisation of malonate derivatives, mediated by hypervalent iodine reagents has also been investigated (Scheme ii). Several lactone derivatives were synthesised with this method, achieving moderate to good yields. Scheme ii. Cyclisation of malonate derivatives to synthesise functionalised lactones. Finally, the design of a new hypervalent iodine reagent is described (Figure i). After its synthesis, the pyridine-based reagent was tested in several model reactions, usually mediated by iodine (III) reagents. Its reactivity was similar to the one of other hypervalent iodine reagents. However, its ability to induce stereoselectivity to different products was quite poor. Figure i. Structure of the new hypervalent iodine reagent.
4
Edmunds, J. J. "Novel fluorination reactions via hypervalent iodine reagents." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47045.
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Gurung, Ras Kumari. "INVESTIGATIONS OF HYPERVALENT IODINE COMPOUNDS IN ORGANIC TRANSFORMATIONS." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/dissertations/991.
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The main aim of the work presented here is to develop new, practical, economical, and environmental friendly synthetic protocols for various organic transformations with hypervalent iodine compounds, which have attracted explosive interest among chemistry communities because of their versatility and mildness in inducing many organic transformations. Chapter 1 briefly introduces the history of hypervalent iodine compounds, nomenclature, classification, bonding and reactivity patterns. The preparation and practical applications of typical I(III) and I(V) compounds have also been briefly surveyed. Chapter 2 provides details on hypervalent iodine compounds catalyzed oxidation of benzylic C-H to the corresponding carbonyl compounds with Oxone. The catalytic efficiency is influenced by the rate of in situ generation of catalyst with Oxone and their stability. The effectiveness in situ generated 35', 50' and 51' are almost the same, leading to low to moderate yields of products, while 18 and 47' give moderate to high yields. Compound 48' was founds to be the most active catalyst in this study. A possible mechanism is also proposed. Chapter 3 covers a surprising reaction between IBX or IBA and alkyl halides promoted by quaternary ammonium halides. In the absence of quaternary ammonium halides, no reaction occurred between IBX or IBA and alkyl halides. However, in the presence of quaternary ammonium halides, IBX or IBA and alkyl halides react smoothly to form the corresponding alkyl iodobenzoates. When IBX or IBA is treated with a quaternary ammonium halide, it will decompose to 2-iodobenzoic acid. The presence of a nucleophilic halide ion is essential for such reaction to occur. Replacing halides with non-nucleophilic BF4- halts the reaction. Benzylic halides provides a better yield than aliphatic alkyl halide. Thus, it is believed that there is a fast interaction between the nucleophilic halides and electrophilic iodine in IBX or IBA. A plausible reaction mechanism is proposed. Chapter 4 details our research on the oxidative cleavage of C=C with PIFA/water. In the presence of a small amount of water in acetonitrile at 65-70 oC, [bis(trifluoroacetoxy)iodo]benzene (PIFA, 26) converts styrenes into benzaldehydes in good to high yields. Contrary to literature description that electron-rich styrenes primarily produces phenylacetaldehydes as major products through a 1, 2-phenyl migration, we have found that these styrenes can be converted to benzaldehydes in high yields. It was found that three equiv of 26 and one equiv of water were necessary to achieve high yields. Two pathways were believed responsible for the high yield of benzaldehydes: (1) cleavage of the glycol intermediates; (2) further oxidative cleavage of the 1, 2-phenyl migration product - phenylacetaldehydes. Chapter 5 describes a preliminary investigation on perfluoroalkylation reaction of styrene with [bis(trifluoroacetoxy)iodo]butane (32). p-t-Butylstyrene reacts with 32 in the presence of water produced moderate yields of hydroxyperfluorinated product, 1-(4-tert-butyl-phenyl)-3,3,4,4,5,5,6,6,6-nonafluoro-hexan-1-ol (73), along with 1-(4-tert-butyl- phenyl)-2-iodo-ethanol (72) and 1-(4-tert-butyl-phenyl)-ethane-1,2-diol (74). Electrophilic addition of 32 on the C=C bond, hydration of the intermediate, and reductive elimination were believed to have been involved. Chapter 6 summarizes all of the work carried out in the previous chapters and provides some insight into future studies.
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Romero, Segura Rafael Martín. "Development of hypervalent iodine(iii)-mediated chemical reactions." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/402470.
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El iode hipervalent representa una poderosa eina per dur a terme diferent reaccions d’oxidació en condicions lliures de metalls. S’han realitzat estudis mecanístics que inclouen experiments de control físic-orgànics relatius a la diaminació intermolecular d’alquens mediats per iode(III) que han servit per a demostrar la veracitat dels càlculs computacionals realitzats prèviament.
Aquesta informació va proporcionar una visió crucial per al desenvolupament d’una nova reacció enantioselectiva de diaminació d’estirens catalitzada per iode(III). El disseny d’un nou catalitzador quiral de iode basat en l’ús de l’àcid làctic com a font econòmica de quiralitat representa la clau d’aquest assoliment. L’optimització del catalitzador implica l’increment de la densitat d’electrònica en el nucli de iode i un motiu d’amida secundària en la cadena lateral de lactat quiral. Entre els diferents oxidants terminals, el mCPBA ha resultat ser el més eficient conduint a bons rendiments i excel·lent enantioselectivitats (>99% ee). L’abast de la reacció comprèn alquens terminals i alquens interns dins del motiu de l’estirè.
En un estudi addicional, es va aconseguir la formació d’un nou enllaç carboni-bor. Així doncs, la borilació de sals de diariliodoni va ser possible després d’identificar el contra-anió del reactiu de diariliodoni més adequat. Mitjançant la generació in situ umpolung al centre de bor, la seva arilació per el reactiu hipervalent esdevé possible. Amb aquest fi, diferent acetats de diariliodoni van ser sintetitzats, demostrant la gran aplicabilitat d’aquest nou mètode respecte al grup aromàtic transferible. Aquest mètode s’afegeix a l’escàs nombre de reaccions de borilació en condicions lliures de metalls.Los reactivos de iodo hipervalente representan una herramienta muy poderosa para la realización de diferentes oxidaciones libres de metal. Se llevaron a cabo estudios mecanísticos incluyendo experimentos físico-orgánicos de control respecto a la diaminación intermolecular de alquenos, demostrando la veracidad de los cálculos DFT previamente realizados. Esta información resultó crucial para el desarrollo de una pionera diaminación enantioselectiva de estirenos catalizada por iodo(III). Uno de los mayores logros es el diseño de un nuevo catalizador de iodo quiral basado en el ácido láctico como fuente económica de información estereoquímica. La optimización del catalizador incluye un aumento crucial de electrondensidad en el núcleo de iodo y la presencia del grupo amida en la cadena de lactato quiral. Entre los diferentes oxidantes terminales probados, mCPBA resultó ser el más eficiente, dando buenos rendimientos y una enantioselectividad sin precedentes, siendo ésta siempre superior al 90% ee. Esta reacción puede extenderse a alquenos terminales e internos que contengan la estructura de estireno. Este logro representa uno de los resultados más avanzados en la diaminación asimétrica de alquenos. En un estudio adicional, se consiguió una nueva formación de enlaces carbono-boro. Aquí, la borilación de sales de diariliodonio fue posible tras la identificación de un contraión apropiado en el reactivo de diariliodonio. Gracias a la generación in situ de un umpolung en el centro de boro, su arilación por el reactivo hipervalente es posible. Con esta finalidad, se sintetizaron diferentes acetatos de diariliodonio y se demostró la gran aplicabilidad de esta metodología en la transferencia de grupos aromáticos. Este protocolo representa uno de los pocos procesos económicos de borilación en ausencia de metal.
Hypervalent iodine(III) reagents represent a powerful tool for the realisation of different metal-free oxidation reactions. Mechanistic studies including physical-organic control experiments concerning the oxidative iodine(III)-mediated intermolecular diamination of alkens were carried out, demonstrating the veracity of previous DFT calculations. This information provided crucial insight for the development of a pioneering iodine(III)-catalysed enantioselective diamination of styrenes. The design of a novel chiral iodine catalyst based on lactic acid as economic chiral information source represents the key accomplishment. Catalyst optimisation involves a crucial electrondensity enhancement at the iodine core and a secondary amide motive in the chiral lactate side chain. Among different terminal oxidants, conventional mCPBA emerged as the most efficient one leading to good yields and unprecedented enantioselectivities of above 90% ee. The scope of the reaction comprises terminal and internal alkenes within the styrene motif. It represents the state of the art in asymmetric diamination of alkenes. In an additional study, a novel carbon-boron bond formation was accomplished. Here, borylation of diaryliodonium salts was encountered feasible upon identification of a suitable counterion in the diaryliodonium reagent. By generating an in situ umpolung at the boron centre, its arylation by the hypervalent reagent becomes viable. To this end, different diaryliodonium acetates were synthesised, thereby successfully demonstrating a broad applicability of this new methodology regarding the transferable aromatic group. This protocol adds to the still scarce number of economic borylation reactions under metal-free conditions.
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Page, Thomas Keri. "Synthesis and reactivity of chiral hypervalent iodine compounds." Thesis, Cardiff University, 2009. http://orca.cf.ac.uk/54874/.
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Hypervalent iodine compounds are molecules of increasing interest to the synthetic chemist. Their low toxicity when compared to heavy metal reagents and their ease of use in the laboratory are helping to establish them into the armoury of the synthetic chemist. More recently, research into chiral hypervalent iodine compounds has been the main focus. The work performed during this research tenure is based upon the development of new chiral hypervalent iodine reagents for use in stereoselective synthesis and this research can be summarised into three main sections: Synthesis of novel chiral iodine(III) compounds; Reactivity of chiral iodine(III) compounds; Novel oxididative procedure. The synthesis of new chiral iodine(III) compounds and their use in asymmetric oxidative functionalisations are described herein. The use of stoichiometric quantities of these iodine(III) reagents with 1 eq of pTsOHO in the a-oxytosylation of ketones and 2 eq of /7TSOH H2 O in the dioxytosylation of alkenes, have given the corresponding products in good yields, 57-76% (3-12% ee) and 48-75% (9-16% ee) respectively. Additionally, a new catalytic method is described in which the presence of a stoichiometric oxidant, 1 eq of /7TSOH H2O and only catalytic quantities of the chiral iodine(I) reagent is necessary to afford a-oxytosylated ketones. The final aspect of the research has dealt with the problems associated with oxidizing iodine(I) compounds to iodine(III) compounds. The development of a new method to oxidise iodine(I) compounds to bis(trifluoroacetoxy)iodo arenes through the use of urea-hydrogen peroxide adduct and trifluoroacetic anhydride is also described.
8
Jegasothy, Shankar. "Kinetic studies on polymer-supported hypervalent iodine oxidants." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615044.
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Wu, Yichen. "Hypervalent Iodine as Directing Tool in Iodine-Retentive Transformation of C-H Bonds." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/461093.
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La química del iode hipervalente és una potent i versàtil eina en síntesi orgànica. En particular, els compostos orgànics de iode (III) s'han utilitzat com a oxidants de 2 electrons, així com agents de transferència de grups en diversos processos oxidatius de funcionalització. Al marge d'un nombre reduït de casos especials, aquestes transformacions van acompanyades per la pèrdua del fragment corresponent a una molècula de iodoarè. Una opció menys explorada, però sintèticament atractiva, consisteix en la incorporació tant del grup orgànic com de l'àtom de iode en el producte final. Aquest enfocament presenta un clar interès sintètic atès que la retenció de l'àtom de iode possibilita la posterior derivatització. Al llarg d'aquesta Memòria es mostren diferents reaccions d'acoblament dirigides per iode partint de compostos de iode trivalent com a substrats.
En primer lloc, es descriu un nou mètode de α-arilació directa de cetones en absència de metalls. La transferència del grup aril té lloc via acoblament orto al iode, i es basa en l'activació in situ d’aquest àtom. El nou procediment presenta bona tolerància als diferents grups funcionals del areno. La selectivitat orto es va relacionar, mitjançant càlculs DFT, amb un procés de reordanament iodonio-Claisen amb una barrera d’activació inusualment baixa. S'ha desenvolupat també un nou tipus de reaccions de benzilació regioselectiva de l'anell aromàtic a partir de derivats Ar(OAc)2 i bencil(trimetil)silà. Cal destacar que aquest procés l'acoblament carboni-carboni té lloc selectivament en la posició para respecte de l'àtom de iode. Per últim, es presenta una nova estratègia per a un procés de "iodoarilació" oxidant de l’anell imidazolic. Aquest procediment es basa en l'activació de l'enllaç NH de l'imidazol amb ArI(OAc) 2, seguida per una transferència 1,3 I-a-N del grup que dona lloc a l'obtenció de N1-aril-5-yodoimidazoles. L'impacte sintètic de la transformació emana de la inherent capacitat dels N1-aril-5-iodoimidazols d'actuar com a precursors per a diversos derivats 1,5-substituïts d'imidazol.La química del yodo hipervalente es una potente y versátil herramienta en síntesis orgánica. En particular, los compuestos orgánicos de yodo(III) se han utilizado como oxidantes de 2 electrones, así como agentes de transferencia de grupos en diversos procesos oxidantes de funcionalización. Salvo unas pocas excepciones, estas transformaciones van acompañadas por la pérdida del fragmento yodobenceno. Una opción menos explorada, pero sintéticamente atractiva, consiste en la incorporación tanto del grupo orgánico como del átomo de yodo en el producto final. Este enfoque presenta un claro interés sintético dado que la retención del átomo de yodo posibilita su posterior derivatización. A lo largo de esta Memoria se muestran distintas reacciones de acoplamiento dirigidas por el yodo partiendo de compuestos de yodo trivalente como sustratos. En primer lugar, se describe un nuevo método de α-arilación directa de cetonas en ausencia de metales. La transferencia del grupo arilo tiene lugar vía acoplamiento orto al yodo, y se basa en la activación in situ del átomo de yodo. Este procedimiento presenta buena tolerancia a los distintos grupos funcionales del areno. La selectividad orto se relacionó, mediante cálculos DFT, con un mecanismo de reorganización yodonio-Claisen con una barrera de activación inusualmente baja. Se ha desarrollado también una nueva vía de acceso para reacciones de bencilación regioselectiva del anillo aromático del ArI(OAc)2 con benciltrimetilsilano. Es interesante destacar que este proceso el acoplamiento carbono-carbono tiene lugar selectivamente en la posición para respecto del átomo de yodo. En último lugar, se presenta una nueva estrategia para la “yodoarilación” oxidante de imidazoles. Este procedimiento se basa en la activación del anillo NH-imidazólico con ArI(OAc)2, seguida por una transferencia 1,3 I-a-N del grupo arilo para la obtención de N1-aril-5-yodoimidazoles. El impacto sintético de la transformación emana de la inherente capacidad de los N1-arilo-5-iodo-imidazoles de actuar como precursores para diversos derivados 1,5-sustituidos de imidazol.
The chemistry of organic hypervalent iodine compounds has been a potent and versatile toolbox in organic synthesis. In particular, organic λ3-iodanes have been utilized as terminal 2-electron oxidants, as well as group transfer agents in a wide range oxidative functionalization processes. With few exceptions, such transformations are accompanied by the liberation of the parent organoiodine fragment. A less explored, but synthetically attractive possibility consists in incorporating both the organic group and the iodine atom into the final product. Such approach presents a clear synthetic appeal, given that the iodine retention opens the door for downstream derivatization. This thesis describes a series of such “iodine-directed” coupling reaction employing organo-λ3-iodanes as substrates. In one approach, a new method for direct metal-free α-arylation of ketones is described. The aryl transfer takes place via the coupling ortho to iodine, and is based on in situ hypervalent activation of the iodine atom. The protocol shows good functional group compatibility on the arene core. The ortho-selectivity was rationalized by DFT calculations through an unusual low-barrier “iodonio-Claisen¨ process. We also developed a new approach for regioselective benzylation of the ArI(OAc)2 cores using benzyltrimethylsilane. Interestingly, the carbon-carbon coupling now takes place selectively at para position to the iodine atom. Finally, an approach for oxidative “iodoarylation” of imidazoles was uncovered. The procedure relies on an efficient activation of the parent NH-imidazole with ArI(OAc)2, followed by copper-catalyzed intramolecular 1,3 I-to-N aryl transfer to constitute the synthetically challenging N1-aryl-5-iodoimidazoles. The importance of this manifold resides in the ability of the 5-iodoimidazoles to act as precursors for a range of 1,5-substituted imidazoles.
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Jain, Nikita. "Chiral hypervalent iodine mediated enantioselective oxidative dearomatization of naphthols." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62521.
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This dissertation investigates and describes the hypervalent iodine mediated dearomatization of naphthols, thereby yielding diversity of spiro-heterocyclic compounds in both racemic and chiral form.
The first part of this thesis discloses the synthesis of racemic spiropyrrolidines and spirolactams via oxidative amidation of corresponding naphtholic sulfonamides, employing DIB as the oxidant. Enantioselective variant of the same have been demonstrated by using in situ generated chiral hypervalent iodine to provide chiral spiropyrrolidines. A noteworthy side reaction discovered in the course of these studies is the asymmetric oxidative addition of meta-chlorobenzoic acid to the naphtholic sulfonamides. The resulting acyloxylated adducts were formed with a greater degree of asymmetric induction compared to spiropyrrolidines in the same reaction mixture. Based on the results obtained from optimization study and substrate scope, plausible mechanistic insights of both cyclization and acyloxylation reactions have been provided.
The second part of this thesis unravels the spiroetherification of naphtholic alcohols, thereby yielding spiroethers both in racemic and chiral form. Chiral hypervalent iodine reagents generated in situ provided a range of spiroethers with excellent ee’s and high yields. These chiral oxidants have been evaluated for kinetic resolution of naphtholic primary alcohols bearing stereogenic center at β-position in the side chain.Science, Faculty of
Chemistry, Department of
Graduate
11
Rose, Helen Louise. "New reactions of hypervalent iodine reagents with nitrogen compounds." Thesis, Keele University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283978.
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Edwards, Richard. "Synthesis of [18F]F-DOPA using hypervalent iodine compounds." Thesis, Cardiff University, 2015. http://orca.cf.ac.uk/84846/.
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[18F]F-DOPA is a widely used radiotracer most commonly employed in the diagnosis of Parkinson’s disease[1] and neuroendocrine tumours (NETs).[2] In this thesis, the syntheses of suitable diaryliodonium salt precursors for [18F]F-DOPA production via fluorination with nucleophilic, no carrier added (n.c.a.) [18F]fluoride are described. The complex iodonium salt precursors are prepared by a simple and robust procedure in good yields and are bench stable compounds. Incorporation of both ‘cold’ [19F]fluoride and ‘hot’ [18F]fluoride using the prepared precursors has been investigated.[3] Fluorinations occur with complete regioselectivity for fluorination at the DOPA moiety when using a range of precursors with varying protecting group strategies. Optimisation of the radiofluorination and subsequent isolation method allowed for isolation of a protected [18F]F-DOPA species in 2% radiochemical yield (RCY). Solid-Supported Iodonium Salts for Fluorinations (CH3) Secondly, solid-supported iodonium salt precursors have been prepared and used for the production of fluoroarenes. The importance of the resin functionality for the attachment of the iodonium salt moieties has been demonstrated. Use of a tris(aminoethyl) funtionalised resin rather than aminomethyl resin as starting material gives improved reproducibility and yields for precursor formation. The successful radiofluorination of a simple solid-supported precursor with no carrier added (n.c.a) [18F]fluoride is also reported, producing [18F]fluorobenzene with 3% radiochemical conversion (RCC).[4] Extension of the solid-supported methodology to the production of synthetically useful fluoroarenes was investigated. Preparation of benzyl protected 4-fluorophenol was accomplished using this strategy. Optimisation of the fluorination conditions gave 24% yield of the aryl fluoride from the resin bound iodonium salt precursor.
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Nocquet-Thibault, Sophie. "La difonctionnalisation d’énamides en utilisant des dérivés d’iode (III) hypervalent." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112270/document.
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Lors de ce travail de thèse qui visait à développer une méthode générale d’introduction d’halogénures et de pseudo-halogénures en se basant sur l’utilisation de réactifs d’iode hypervalent en tant que promoteurs d’umpolung, diverses avancées ont pu être accomplies. Tout d’abord, une réaction d'alkoxybromation régiosélective mettant en jeu des sels de bromure et du PIDA a été mise au point. Un des intérêts de cette réaction réside dans l'utilisation de LiBr peu coûteux comme source d'halogène électrophile (par inversion de polarité : umpolung). En outre, l'introduction de deux groupements de manière chimio- et régiosélective est possible sans recourir à l'utilisation d’un catalyseur métallique. Une large gamme d'énamides a été testée et les rendements sont généralement excellents (au dessus de 75 %) et les réactions rapides (moins d’une heure). En outre, la diastéréosélectivité oscille entre modérée et excellente. Ces produits éthoxybromés se sont aussi montrés très polyvalents et permettent l’accès à de nombreux motifs structuraux. Une version asymétrique de cette réaction en faisant intervenir des dérivés d’iode hypervalent chiraux n’a pas été couronnée de succès tout comme l’introduction de copules chirales. Le but initial était de mettre au point une méthode générale de difonctionnalisation d’énamides avec l’insertion d’halogénures. C’est pourquoi, notre stratégie a ensuite été étendue au chlore et une réaction d’éthoxychloration a été développée avec des rendements moyens à très bons (de 36% à 86%) un temps de réaction rapide (généralement autour de 30 minutes) et une diastéréosélectivité moyenne à très bonne (de 55/45 à 92/8). Les deux réactions d’éthoxybromation et d’éthoxychloration ont fait l’objet d’une investigation mécanistique (notamment par spectrométrie de masse) et il semblerait que le mécanisme soit ionique. Nous avons alors voulu appliquer cette méthodologie au fluor, élément dont l’introduction sélective sur un substrat est rarement triviale. En accord avec la littérature, nous avons conclu que le fluor ne pouvait être transféré directement en tant qu’électrophile. Enfin, une version d’éthoxyiodation a été validée et est en cours d’optimisation au laboratoire. Concernant les pseudo-halogénures, nous nous sommes uniquement intéressés aux azotures. Ayant réalisé qu’une réaction d’éthoxyazidation ne serait pas possible, une étude poussée des différents paramètres réactionnels adossée à la compréhension des mécanismes mis en jeu a été entreprise. Deux méthodologies ont alors pu être mises au point : une réaction de diazidation dont les rendements sont modérés ( entre 20% et 52%), les temps de réaction courts (environ 1 h) et des diastéréosélectivités moyennes à bonnes (entre 75/25 et 90/10) ainsi qu’une réaction d’oxyamination qui se montre bien plus efficace avec des rendements moyens à très bons (de 31% à 95%), des temps de réaction assez rapides (autour de 2 h), des diastéréosélectivités souvent excellentes (supérieures à 67/33) et un champ d’application bien plus large (Schéma 245). Ces deux méthodes réunies représentent un outil utile pour l’obtention de composés à la fois azotés et azidés. Dans ce cas, les intermédiaires réactionnels semblent être radicalaires même si des études complémentaires restent à effectuer.L’intérêt synthétique de ces deux types de composés a aussi fait l’objet de diverses études. Si la réduction du groupement azido en amine n’a pas pu être systématiquement accomplie, des réactions de cyclisation d’Huisgen sur les produits diazidés ont cependant fonctionné (les produits oxyaminés semblant trop encombrés stériquement). Quant au groupement TEMPO il a notamment pu être oxydé en cétone. Ainsi, des outils méthodologiques ont été développés lors de cette thèse, pour la difonctionnalisation oxydante d’énamides par des dérivés d’iode (III) hypervalent et en particulier, l’introduction d’halogénures et d’azoturesHypervalent iodine compounds such as (diacetoxyiodo)benzene (PIDA) are non-toxic and mild reagents that can behave in similar fashion to transition-metal complexes. Indeed, around the central iodine atom, ligands can be exchanged and then transferred through a formal reductive elimination. Following this strategy, halides can be used as ‘ligands’, in which case an umpolung of the salt can occur to give birth to electrophilic halogen species. Using LiBr, ethanol and PIDA, a variety of enamides underwent a regioselective ethoxybromination with high yields, short reaction time and good to excellent diastereoselectivity. One of the main interests of this reaction lies in the use of a cheap and widely available bromide salt (LiBr) to generate electrophilic halogen species by umpolung. Moreover, despite the oxidative nature of the reaction conditions, a wide scope of functional groups (olefins, esters, alcohols…) is tolerated. This reaction provides α-bromo-hemiaminals which are highly versatile synthons. For instance, various nucleophiles can be incorporated on the hemiaminal moeity and then engaged in further transformations. The development of an asymmetric variant of this transformation using chiral pool or chiral hypervalent iodine was unsucceful. This methodoly has been extended to the umpolung of other salts as chlorine with moderate to good yields (from 36% to 86%) and a moderate to very good diastereoselectivity (from 55/45 to 92/8) with a short reaction time (30 minutes). Mechanistic investigation for both reactions has been performed and an ionic parthway has been priviledge. The introduction of fluorine as an electrophile was not possible according to the litterature.Finally, the last halide, iodine can be tansfered and an ethoxyiodation reaction is under optimisation. Concerning the pseudo-halides, we devot a special attention to azides. Two methodologies has been set up : a diazidation reaction which yields are moderate (betwwen 20% and 52%), short reaction times (around 1 h) and moderate to good diastereoselectivity ratios (between 75/25 and 90/10) and an oxyamination reaction whiwh shows to be much more efficient with moderate to very high yields (from 31% to 95%), short reaction times (around 2 h), excellent diastereoselectivity ratio (superior to67/33). These two gathered reactions represent a useful tool for the introduction of a nitrogen. For the diazidation reaction, the intermediatories seem to be radicals whereas for the oxyamination reaction probably ionic species. . Thus, synthetic tools have been developped during this thesis for the difunctionnalisation of enamides by hypervalent iodine and particulary introduction of halides and azides
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Lucchetti, Nicola. "New Perspectives in Aromatic Aminations Using Hypervalent Iodine(III) Reagents." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/450871.
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L’objectiu principal d’aquesta tesi doctoral ha sigut el desenvolupament de noves metodologies catalítiques i estequiomètriques per a l’aminació d’anells aromàtics sense fer ús de metalls. En aquest sentit, s’ha descrit el primer exemple d’una eliminació reductora en una espècie de iode(III), utilitzant sals de diariliodoni i imides com a font de nitrogen. L’estudi del perfil cinètic de la transformació ha permès calcular els seus paràmetres energètics, que estan en concordança amb les dades experimentals. El protocol desenvolupat presenta una àmplia generalitat per a la síntesi d’anilines 2,6-substituïdes, estèricament impedides, incloent també amides i lactames com a cosubstrats en la reacció d’acoblament. S’ha provat la seva utilitat sintètica mitjançant la seva aplicació en una síntesi en dos passos de una N,N’-diaril pirrolidinoncarboxamida. Aquest compost pertany a una família d’inhibidors de l’enllaç del pèptid quemerina amb el receptor ChemR23 de la proteïna G.
El següent pas en la recerca de noves aproximacions lliures de metall ha sigut la implementació de 1,2-diiodebenzè com a precatalitzador. El mecanisme de reacció, en contrast amb el de les sals de iodoni(III) anteriors, implica un nitrogen (catió) electròfil. Resulta interessant que, a diferència de les anteriors propostes, en aquest cas es pugui assumir que ambdós iodes del bis(iode)arè juguen un paper actiu. Aquest fet ha estat confirmat mitjançant la caracterització de l’intermedi de iode(III) per difracció de raigs X, que mostra un anell distorsionat de cinc membres. En comparació amb altres protocols descrits, els valors de TON (número de cicles catalítics per molècula de catalitzador) i les regioselectivitats exhibides són superiors.El objetivo principal de esta tesis doctoral ha sido el desarrollo de nuevas metodologías catalíticas y estequiométricas para la aminación de anillos aromáticos sin empleo de metales. Para ello, se ha descrito el primer ejemplo de una eliminación reductora en una especie de yodo(III), utilizando sales de diarilyodonio e imidas como fuente de nitrógeno. El estudio del perfil cinético de la transformación ha permitido calcular sus parámetros energéticos, los cuales concuerdan con los datos experimentales. El protocolo desarrollado presenta una amplia generalidad para la síntesis de anilinas 2,6-disustituídas, estéricamente impedidas, incluyendo también amidas y lactamas como co-sustratos en la reacción de acoplamiento. Se ha demostrado su utilidad sintética mediante la realización de una síntesis en dos pasos de una N,N’-diaril pirrolidinoncarboxamida. Este compuesto pertenece a una familia de inhibidores del enlace entre el péptido quimioatractivo quemerina y el receptor ChemR23, acoplado a la proteína G. El siguiente paso en la búsqueda de nuevas aproximaciones sin empleo de metales ha sido la implementación de 1,2-diyodobenceno como precatalizador. El mecanismo de reacción, en contraste con el de las sales de yodonio(III) anteriores, implica un intermedio de nitrógeno electrófilo. Resulta interesante que, a diferencia de las propuestas anteriores, en este caso se ha podido demonstrar que ambos iodos en el bis(yodo)areno desempeñaban un papel activo. Este hecho ha sido confirmado mediante el aislamiento y caracterización por difracción de rayos X del intermedio de yodo(III), mostrando éste un anillo distorsionado de cinco miembros. El valor de TON (turnover number) y las regioselectividades exhibidas fueron superiores en comparación a otros protocolos descritos.
The main objective of this doctoral thesis was the development of new stoichiometric and catalytic methodologies for the metal-free amination of aromatic cores. The first example of reductive elimination at an iodine(III) centre using diaryliodonium salts and imides as nitrogen sources has been reported. The study of the kinetic profile of the transformation allowed the calculation of the energetic parameters, which were in agreement with the experimental data. The developed protocol was of broad scope for the synthesis of congested 2,6-disubstituted anilines, including also amides and lactams as amino coupling partners. The synthetic utility was demonstrated by the two-step-synthesis of an N,N’-diarylated pyrrolidinone carboxamide. This compound belongs to a family of binding inhibitors of the chemo-attractant peptide chemerin to the G-protein coupled receptor ChemR23. The subsequent step in the search for new metal-free approaches was the use of 1,2-diiodobenzene as precatalyst. The mechanism of the reaction, differently to the previous iodonium(III) salts, involved an electrophilic nitrogen intermediate. Interestingly, in sharp contrast with the previous proposals we could proof an active role of both iodine centres in the bis(iodo)arene. This was confirmed by the isolation and characterisation by X-ray diffraction of the oxidised iodine(III) intermediate, which showes a distorted five-membered ring. The exhibited turnover numbers (TON) and the regioselectivities were superior to all the other reported protocols.
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Farid, Umar. "Stereoselective reactions of alkenes mediated by chiral hypervalent iodine reagents." Thesis, Cardiff University, 2013. http://orca.cf.ac.uk/53180/.
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Chiral hypervalent iodine compounds are used as environmentally friendly, mild, and selective oxidants for many organic transformations. In this thesis, enantiomerically pure chiral hypervalent iodine reagents have been synthesized and used in the functionalization of different types of alkenes. A highly enantioselective oxyamination of alkenes with N-sulfonyl ureas employing chiral lactic acid-based hypervalent iodine reagents giving a facile synthesis of enantiomerically pure 2- arylproline derivatives is described. This is the first example of stereoselective oxyamination reactions under metal-free conditions. Then oxidative rearrangement of aryl-substituted ketones induced by lactate acid-based chiral hypervalent iodine reagents via 1,2 migration of the aryl moiety in the presence of alcohol nucleophiles is described leading to the �-arylated and �-oxygenated carbonyl compounds in enantiomerically pure form. This is the first stereoselective rearrangement reaction mediated by chiral hypervalent iodine reagents. Finally, all experimental details and characterization of the compounds are described.
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McLaren, Lee. "Synthetic applications of hypervalent iodine reagents : total synthesis of aranorosin." Thesis, University of East Anglia, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385890.
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Koyuncu, Demet. "Functional group oxidations using sodium perborate and hypervalent iodine reagents." Thesis, University of East Anglia, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303030.
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Eisenberger, Patrick. "The development of new hypervalent iodine reagents for electrophilic trifluoromethylation." kostenfrei, 2007. http://e-collection.ethbib.ethz.ch/view/eth:29987.
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Antien, Kevin. "Développement de nouveaux réactifs iodés hypervalents chiraux hélicéniques. Synthèse collective stéréodivergente d’alcaloïdes de Securinega." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0349/document.
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La chimie des composés iodés hypervalents, ou organoiodanes, suscite un engouement croissant de la part de la communauté scientifique depuis maintenant près de 30 ans. Les efforts de recherche sont de nos jours orientés de manière prépondérante vers des applications en synthèse asymétrique, principalement au travers de l’utilisation d’architectures organoiodées chirales. À ce jour, seules les chiralités centrales et axiales sont exploitées dans l’élaboration de tels objets. L’emploi d’iodanes achiraux (i.e. en synthèse asymétrique) en présence d’additifs chiraux a par ailleurs été largement négligé par la communauté. La chiralité hélicoïdale est incarnée en chimie organique par les hélicènes. Ces composés polyaromatiques sont des objets fascinants de par leurs propriétés structurelles, électroniques et chiroptiques hors du commun. Ils sont le centre d’une attention considérable dans de nombreux domaines de recherches allant de la catalyse asymétrique à l’élaboration de diodes électroluminescentes organiques. Jamais la chiralité hélicoïdale n’a été exploitée en chimie de l’iode hypervalent. Ces travaux de thèse traitent en premier lieu de l’élaboration d’une méthodologie asymétrique de désaromatisation oxygénante de phénols faisant usage d’un iodane-3 achiral en présence d’un agent de transfert de phase issu des alcaloïdes du Quinquina. Dans une seconde partie de ces travaux est abordée la synthèse asymétrique d’un nouvel iodoarène hélicénique et ses premières applications dans des réactions de désaromatisation oxygénante de phénols. Cet ouvrage traite également dans un troisième chapitre d’une synthèse totale, collective et stéréodivergente de 12 alcaloïdes de Securinega. Il s’agit d’une classe métabolites secondaires retrouvés dans de multiples plantes des genres Securinega (Flueggea), Phyllanthus, Margaritaria et Breynia de la famille Phyllanthaceae. Depuis près d’un demi-siècle, la biogénèse de ces molécules naturelles demeure partiellement incomprise. La synthèse développée dans ce travail a pour vocation d’améliorer la compréhension du mécanisme biosynthétique à l’origine de ces substances. Il a ainsi été établi qu’une étape clé de condensation aldolique pourrait permettre d’expliquer la stéréodivergence observée dans la natureHypervalent iodine chemistry has been arousing the interest of the scientific community for the last 30 years. Research efforts are now mainly directed towards applications in asymmetric synthesis, notably through the use of chiral organoiodine scaffolds. To this end, solely central and axial chiralities have been exploited to construct such objects. The use of achiral iodanes (i.e. hypervalent organoiodine compounds) in asymmetric synthesis has been largely neglected by the community. Helical chirality in organic synthesis is mainly found in polyaromatic compounds known as helicenes. These molecules exhibit fascinating structural, electronic and chiroptical properties. They are the center of considerable attention across many fields of research, spanning from asymmetric catalysis to organic light-emitting diodes. Helical chirality has never been exploited in the field of hypervalent iodine chemistry. In the first part of this doctoral work, a methodology for the asymmetric oxygenative dearomatization of phenols by an achiral 3-iodane in the presence of a Cinchona-alkaloid-based phase transfer agent was developed. The second part of this manuscript details the synthesis of a new helicenic organoiodine compound and its application to oxygenative phenol dearomatization reactions. In the last chapter of this doctoral dissertation is described the total, collective and stereodivergent synthesis of 12 Securinega alkaloids. These natural products are commonly found in plants belonging to the genera Securinega (Flueggea), Phyllanthus, Margaritaria and Breynia of the Phyllanthaceae family. Even after little less than half a century of research, the real biogenetic pathway used by nature to construct these molecules is still only partly understood. The chemical synthesis developed in this doctoral work provides a better understanding of the biosynthetic mechanism. It was established in the course of this work that a key aldol condensation step could shed light upon the stereodivergence observed in nature
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Kamouka, Somaia Taher. "Development of enantioselective and catalytic cyclisation reactions using hypervalent iodine compounds." Thesis, University of Huddersfield, 2017. http://eprints.hud.ac.uk/id/eprint/34150/.
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In this thesis, iodoarene and chiral iodoarene reagents have been developed and used catalytically in the enantioselective cyclisation reaction of unsaturated esters, amides and β-amidoketones. The results in this thesis are divided into three parts. In the first part, the development of the catalytic enantioselective cyclisation of 4-methoxy but-3-enyl benzoate to the 3-hydroxytetrahydrofuran ester using enantiomerically pure chiral hypervalent iodine reagents generated in situ is described. A good enantioselectivity of 77% ee was obtained with moderate yield. In the second part, the development of catalytic conditions for the cyclisation of N-alkenylarylamides induced by iodoarenes leading to the formation of different ring sizes is demonstrated. In addition, the catalytic enantioselective cyclisation of N-alkenylarylamides employing chiral iodoarenes giving dihydrooxazines in good yields and moderate enantioselectivities of up to 64% is achieved. In the third part, the catalytic cyclisation of both propargyl amides and β-amidoketones using 2-iodoanisole to afford 2-oxazolines in good yields is described. Moreover, the catalytic enantioselective cyclisation of β-amidoketones using several chiral iodoarenes is detailed but, unfortunately almost no enantioselectivities was observed.
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Brenet, Simon. "Nouvelle structure BINOL-Maléimide. Applications en catalyse d'oxydation asymétrique." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENV050/document.
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Les réactions asymétriques catalysées constituent une approche élégante au problème de l'introduction de centres stéréogène pour la synthèse de molécules complexes. Dans ce contexte, les oxydations sont notables de par la possibilité de créer en une seule étape à la fois le centre asymétrique ainsi que les fonctions dont les réactivités sont à la base des méthodologies de synthèse. La sélectivité d'un catalyseur est le plus souvent contrôlée par sa structure même. Notre groupe étudie les oxydations aérobies asymétriques par activation C-H par des analogues chiraux du N-hydroxyphtalimide (NHPI). Nous avons développé une nouvelle structure de catalyseur comportant un cœur BINOL-maléimide afin de dépasser les limitations intrinsèque des précédentes générations de catalyseurs. La première série n'a pas montré d'énantiosélectivité, cela nous a conduit a synthétiser une deuxième série dont les caractéristiques permettraient d'améliorer l'efficacité de ces catalyseurs d'oxydation aérobie asymétrique. Le développement d'un analogue portant deux iodes nous a conduit à étudier cette structure en tant que cœur de catalyseurs à base d'iode hypervalent. Nous avons analysé trois séries de ces catalyseurs pour l'oxytosylation de cétones prochirales et montré que notre structure est comparable avec celles présentées dans la littératureCatalysed asymmetric reactions are an elegant approach towards the synthesis of complex molecules for the controlled introduction of stereocenters. Within this field, oxidations are noteworthy since they allow to create in one step both the stereogenic elements and the moieties whose reactivities are the cornerstone of the methodologies of synthesis. The selectivity of a catalyst is most often controlled by its own structure. Our group has investigated catalysed asymmetric aerobic oxidations by C-H activation through the use of chiral analogues of N-hydroxyphtalimide (NHPI). We have developed a new structure of catalyst based upon a BINOL-fused maleimide core to circumvent the inherent limitations of previous catalysts generations. The first series showed no enantioselectivity and led us to synthesize a second series whose features are expected to improve the overall efficiency of those catalysts for asymmetric aerobic oxidations. The development of an analogue bearing two iodine moieties prompted us to study this structure as a core for chiral hypervalent organo-iodine(lll) catalysts. We have investigated three series of such catalysts for the asymmetric α-oxytosylation of prochiral ketones and showed that our structure is comparable with the ones found in the literature
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Peilleron, Laure. "Nouvelle approche synthétique vers des analogues de l'avibactam et cyclisations de N-alkoxyurées insaturées initiées par des réactifs d’iode(III) hypervalent." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS408/document.
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La situation très préoccupante due aux résistances antimicrobiennes incite les chimistes à concevoir de nouvelles molécules capables de lutter contre ces résistances. Les inhibiteurs de β-lactamases diazabicyclooctanes permettent de préserver l'arsenal thérapeutique actuel en restaurant l’activité des antibiotiques β-lactames. Ainsi, l'avibactam a été très récemment approuvé par la FDA et l'EMA en association avec la ceftazidime (une céphalosporine de 3ème génération) pour le traitement des infections sévères de bactéries Gram négatif. Ces composés se caractérisent par une structure bicyclique présentant un motif N-hydroxyurée cyclique qui est la clé de leur activité. Cependant, les méthodes permettant d’accéder facilement à ce type d'hétérocycles saturés, sont peu nombreuses. Dans le cadre de cette thèse, l'objectif était de développer une nouvelle approche synthétique permettant d’accéder à des analogues de l'avibactam. Pour cela, nous avons développé des cyclisations chimiosélectives, initiées par des réactifs d’iode(III) de N-alkoxyurées insaturées. Trois cyclisations différentes ont été optimisées et étudiées, fournissant des oxazolidinones oximes ou des N-oxyimidazolidinones à partir des mêmes substrats, selon des mécanismes distincts. Les différents modes de cyclisation peuvent être contrôlés grâce à l’association d’un réactif d'iode(III) et d'un sel d'halogénure ou de TEMPO, selon des conditions réactionnelles simples à mettre à œuvre. En parallèle, nous avons également réalisé la synthèse asymétrique d'un intermédiaire monocyclique clé, qui devrait conduire à des analogues de l'avibactam grâce à une nouvelle voie de synthèse utilisant la méthodologie de cyclisation développéeThe current dire situation of antimicrobial resistances urges synthetic chemists to design new molecules that can fight these resistances. Hence, the diazabicyclo-octanes β-lactamase inhibitors are of particular interest, as they can preserve the current therapeutic arsenal by restoring the activity of β-lactam antibiotics. Thus, avibactam was very recently approved by the FDA and the EMA in combination with ceftazidime (a 3rd generation cephalosporin antibiotic) for the treatment of severe Gram-negative bacteria infections. Structurally, these compounds are characterized by a bicyclic framework featuring a cyclic N-hydroxylated urea motif that is key to its activity. Yet, only few methods exist to easily access this singular type of saturated heterocycles. The aim of this project was to develop a new synthetic approach to acces a new range of avibactam analogues. For this, we developed chemoselective iodine(III)-mediated cyclizations of unsaturated N-alkoxyureas. We were able to optimize and study three different cyclizations that proceed through distinct mechanisms to yield oxazolidinone oximes, or N-oxyimidazolidinones from the same substrates. The different modes of cyclization can be triggered using a combination of the iodine(III) and a halide salt or TEMPO, under reaction conditions which are operationally simple and easily tunable. In parallel, we also devised asymmetric synthesis of a key monocyclic intermediate which should yield avibactam analogues, through a new synthetic route that relies on the methodology we developed
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Jalalian, Nazli. "Development and Applications of Hypervalent Iodine Compounds : Powerful Arylation and Oxidation Reagents." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-75810.
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The first part of this thesis describes the efficient synthesis of several hypervalent iodine(III) compounds. Electron-rich diaryliodonium salts have been synthesized in a one-pot procedure, employing mCPBA as the oxidant. Both symmetric and unsymmetric diaryliodonium tosylates can be isolated in high yields. An in situ anion exchange also enables the synthesis of previously unobtainable diaryliodonium triflates. A large-scale protocol for the synthesis of a derivative of Koser’s reagent, that is an isolable intermediate in the diaryliodonium tosylate synthesis, is furthermore described. The large-scale synthesis is performed in neat TFE, which can be recovered and recycled. This is very desirable from an environmental point of view. One of the few described syntheses of enantiopure diaryliodonium salts is discussed. Three different enantiopure diaryliodonium salts bearing electron-rich substituents are synthesized in moderate to high yields. The synthesis of these three salts shows the challenge in the preparation of electron-rich substituted unsymmetric salts. The second part of the thesis describes the application of both symmetric and unsymmetric diaryliodonium salts in organic synthesis. A metal-free efficient and fast method for the synthesis of diaryl ethers from diaryliodonium salts has been developed. The substrate scope is wide as both the phenol and the diaryliodonium salt can be varied. Products such as halogenated ethers, ortho-substituted ethers and bulky ethers, that are difficult to obtain with metal-catalyzed procedures, are readily prepared. The mild protocol allows arylation of racemization-prone a-amino acid derivatives without loss of enantiomeric excess. A chemoselectivity investigation was conducted, in which unsymmetric diaryliodonium salts were employed in the arylation of three different nucleophiles in order to understand the different factors that influence which aryl moiety that is transferred to the nucleophile.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Accepted. Paper 5: Submitted. Paper 6: Manuscript.
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Satchwell, P. J. "The synthesis of natural products by phenolic oxidation using hypervalent iodine reagents." Thesis, Swansea University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638773.
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Oxidation of a 2-(4"-hydroxybenzyl)-3-(3',4'dimethoxybenzyl) butyrolactone, using the hypervalent iodine reagents bis(trifluoroacetoxy) iodobenzene (PIFA) or iodobenzene diacetate (PIDA), results in the formation of 3-([1"-hydroxy-4"-oxo-2",5"cyclodienyl] methylene)-4-(3',4' dimethoxy benzyl)-2-(5H)-furanone in high yield. Treatment of 3-([1"-hydroxy-4"-oxo-2",5" cyclodienyl] methylene)-4-(3',4' dimethoxy benzyl)-2-(5H)-furanone with trifluoracetic acid results in rearrangement, to form 11-hydroxy-2-3 dimethoxy dibenzo[1a,4a:8a,12a] cycloocta-6-(hydroxymethyl)-7-(carboxylic acid) lactone, in quantitative yield. Hence we have achieved a highly efficient method to produce isostegane and stegane type lignans. Attempts to modify the oxidation of 2-(4"hydroxybenzyl)-3-(3',4'dimethoxybenzyl) butyrolactone, in order to produce the corresponding quinone methide, gave disappointing results. Oxidation of 2-(4"hydroxy 3",5" dimethoxybenzyl)-3-(3',4'dimethoxybenzyl) butyrolactone using silver complexes resulted in formation of 3',4'dimethoxybenzyl butrolactone. Oxidation of cis-3' hydroxy isoflavan-4-ol, to produce the corresponding pterocarpan, results in oxidation of both hydroxyls to produce a dimethoxy cyclohexadienone in acceptable yields.
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Novak, Andrew. "Developments in the use of organoalanes and hypervalent iodine reagents in synthesis." Thesis, University of Nottingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438358.
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Wang, Han Verfasser], Carsten [Akademischer Betreuer] [Bolm, and Markus [Akademischer Betreuer] Albrecht. "Applications of hypervalent iodine(III) reagents in sulfoximidations / Han Wang ; Carsten Bolm, Markus Albrecht." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1176422162/34.
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Cooke, Michael Liam. "Development of novel arylation and alkenylation reactions using hypervalent iodine reagents and copper catalysis." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609862.
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Kulkarni, Gajanan C. "NEW DESIGN CONCEPTS TOWARDS MOLECULAR BOWLS, HYPERVALENT IODINE BASED MATERIALS, AND ENERGY STORAGE MATERIALS." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/dissertations/1755.
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In this dissertation, new cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs) based on a tetracene core have been developed and shown to be a bridge between the previously reported anthracene and pentacene cores. These tetracene derivatives were prepared by palladium-catalyzed cyclopentannulation between 5,11-dibromotetracene and two diaryl-ethynylene derivatives. The new compounds relatively small band gaps and have low-energy Lowest Unoccupied Molecular Orbitals (LUMOs) and because of their ability to form cyclopentadienyl anion-like structures that are stabilized by Hückel aromatics.2-4. The photooxidative stability was intermediate to previously prepared CP-PAHs based on anthracene and pentacene derivatives. Scholl cyclodehydrogenation of pendant aryl groups led to materials that quickly form endoperoxide products.5, 6 The general photostability of the cyclopentannulated structures match those of traditional acenes (e.g., CP-anthracene > CP-tetracene > CP-pentacene). Moreover, this dissertation will discuss our efforts to use these tetracene derivatives (and others) to form new bowl-shaped molecules. In addition, this dissertation describes efforts towards the development of supramolecular materials based on secondary bonding in hypervalent iodine systems. Star shaped polymers with a core based on a hypervalent iodine macrocycle (HIM) based on amino acid derived benziodazoles was prepared. An arm-first and core-first approach was used to combine the HIM with an atom transfer radical polymerization (ATRP) initiator to form polystyrene arms. While the desired star polymers were observed by gel permeation chromatrography (GPC), the core HIM were found to degrade under the testing conditions and showed large amount of monomer. A description of our synthetic routes to these materials and the attempts at characterization of this system is described. Lastly, this dissertation describes the development of new anolytes for redox flow batteries. A series of pyrilium based materials that can undergo redox reactions were developed and screened for incorporation into flow batteries owing to their reversibility in redox reactions and the relatively high solubility in acetonitrile. However, cyclic voltammetry, spectroelectrochemical analysis, and bulk electrolysis studies have shown that these species are not stable enough to be considered good candidates as anolytes. To address these stability issues, a series of pyridinium anolyte systems that contain bulky isopropyl or t-butyl groups were prepared and evaluated. Unfortunately, the long term stability in the pyridinium species were also found to be unsatisfactory, which clearly demonstrates the importance of electron withdrawing groups to be included in the anolyte design.
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Wang, Han [Verfasser], Carsten [Akademischer Betreuer] Bolm, and Markus [Akademischer Betreuer] Albrecht. "Applications of hypervalent iodine(III) reagents in sulfoximidations / Han Wang ; Carsten Bolm, Markus Albrecht." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1176422162/34.
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Aubineau, Thomas. "Synthèse d'hétérocycles azotés : tétrahydropyrazines et morpholines." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS144/document.
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Les tétrahydropyrazines et les morpholines sont des hétérocycles à six chaînons comportant deux hétéroatomes en position 1,4. Les objectifs de cette thèse ont été la mise au point de nouvelles méthodes pour leur synthèse. Des tétrahydropyrazines orthogonalement protégée ont ainsi été synthétisées à partir des diamines correspondantes, grâce à l’utilisation de triméthylsilyl-benziodoxolone (TMS-EBX) comme donneur d’alcyne. Ce dérivé d’iode hypervalent s’est par ailleurs révélé être un agent alcynylant chimiosélectif des sulfonamides par rapport aux carbamates. Une approche synthétique différente a été utilisée pour le synthèse des morpholines. En s’appuyant sur les précédents résultats obtenus au laboratoire, une hétérocyclisation catalysée au Fe(III) a été mise au point. En présence d’une quantité catalytique de FeCl3.6H2O, des morpholines 2,6- et 3,5-disubstituées ont été obtenues avec de bons rendements et des diastéréosélectivités toujours en faveur des composés cis. Afin d’améliorer cette méthode pour la rendre encore plus éco-compatible, une méthode monotope a été ensuite développée, menant, à l’aide d’une catalyse séquentielle Pd(0)/Fe(III), à une diversité de morpholines à partir de vinyloxiranes et d’amino-alcools facilement synthétisables. Le changement des substrats de départ permet de faire varier la substitution des morpholines finales sans avoir à modifier les conditions réactionnelles. L’obtention majoritaire des composés de configuration relative cis a été rationalisés à partir des stabilités supposées des différents diastéréoisomères et un mécanisme hypothétique est présentéTetrahydropyrazines and morpholines are six-membered heterocycles including two heteroatoms in positions 1 and 4. The objectives of this thesis were to develop new methods for their synthesis. Orthogonnaly protected tetrahydropyrazines were thus synthesized from the corresponding diamines, thank to the use of trimethylsilyl-benziodoxolone (TMS-EBX) as an alkyne donnor. This hypervalent iodine derivative was also found to be an efficient and chemoselective alkynylating agent of sulfonamides versus carbamates. A different synthetic approach was used for the synthesis of morpholines. Relying on previous results obtained in the laboratory, an iron(III)-catalyzed heterocylization was developped. In the presence of a catalytic amount of FeCl3.6H2O, 2,6- and 3,5-disubstituted morpholines were obtained with good yields and diastereoselectivities in favor of the cis compounds. To improve this method and make it more environnementally friendly, a one-pot method was next designed, leading, with a sequential Pd(0)/Fe(III)-catalyzed process, to a diversity of morpholines from readily available vinyloxiranes and amino-alcohols. A simple switch in the starting materials gives diverse morpholines without any change in the reaction conditions. The cis-compound predominance was rationnalized from the putative stabilities of different diastereoisomeres and a hypothetical mechanism is proposed
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Ilchenko, Nadia O. "Novel Applications of Benziodoxole Reagents in the Synthesis of Organofluorine Compounds." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-136207.
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This thesis concerns method development of new synthetic routes by applying electrophilic hypervalent iodine reagents, such as trifluoromethyl-benziodoxole (Togni reagent) and fluoro-benziodoxole. The first project involved the addition of an oxygen moiety and trifluoromethyl group across double and triple bonds (both groups derived from the hypervalent iodine reagent). We observed that electron donating substituents on the aromatic ring of the substrate accelerated the oxytrifluoromethylation reaction. This transformation was further expanded to halo-trifluoromethylation reaction of a vinyl silane substrate. We also developed a copper mediated cyanotrifluoromethylation reaction, which was accelerated by PCy3 additive. This transformation allowed for the creation of two new C-C bonds in a single addition reaction. The direct C-H trifluoromethylation reaction of quinones was achived using the Togni-reagent in the presence of B2pin2 additive. The intriguing additive effects of both B2pin2 and PCy3 inspired us to examine the mechanism of these transformations. Fluoro-benziodoxole is the fluoroiodane analogue of the trifluoromethylating Togni reagent. We developed a AgBF4 mediated geminal difluorination of styrenes using this fluoroiodine reagent. In this process one fluorine atom came from the fluoroiodane, while the other fluorine was derived from the tetrafluoroborate ion. A similar approach was applied for the 1,3-oxyfluorination and difluorination of cyclopropanes. Similarly, this fluorinative ring opening of unactivated cyclopropanes involved the introduction of an electrophilic fluorine atom from the fluoroiodane reagent and a nucleophilic one from the tetrafluoroborate ion. This reaction was extended to synthesis of 1,3-oxyfluorinated products. When alkenes reacted with the fluoro-benziodoxole reagent in the presence of palladium catalyst the iodofluorination reaction occurred. Both the iodine and fluorine atoms were derived from the fluoroiodane reagent. The iodofluorination reaction with disubstituted and cyclic alkenes proceeded with high regio- and stereoselectivity.
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Chun, Joong-Hyun. "NMR Studies of the Hydration Equilibria of Mesylate and Dialkyl Phosphate Derivatives of Acetone; and Investigations of Novel Hypervalent Iodine Compounds." University of Akron / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1131685679.
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Chen, Wei-Ching. "Selective Oxidation of Lignin Models and Extracts with Earth-Abundant Transition Metals and Hypervalent Iodine." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32181.
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As a significant component of lignocellulosic biomass, lignin represents a potential source of value-added aromatic chemicals. In this thesis, catalytic systems with earth-abundant metal catalysts such as molybdenum(VI) and hypervalent iodine complexes were developed to selectively break down lignin models into lower molecular weight chemicals under mild conditions. Due to the complexity of lignin, simple lignin model substrates (A to E), representing common linkages in lignin, were used to investigate the catalytic activity/selectivity of these catalysts. With the molybdenum catalysts [7– 11]/SPC/Adogen®464 system (SPC = sodium percarbonate), oxidation of simple β-1 model compound A in acetonitrile showed primarily C-H bond cleavage to form the ketone product, benzoin methyl ether, whereas the Cα-Cβ bond cleavage product, methyl benzoate, was obtained by switching the reaction solvent to benzonitrile. Preference for generating the Cα-Cβ bond cleavage product, i.e. benzaldehyde, can also be achieved with other early to middle transition metal catalysts using H2O2(aq) as the terminal oxidant. Stoichiometric amounts of hypervalent iodine/Lewis acid systems [20a-c] were able to selectively cleave Cα-Cβ bonds to aldehydes with both simple β-1 model compound A and β-O-4 model compound C. In contrast, other lignin model compounds with different linkages were unable to be oxidized to a great extent using these Mo- or iodine-based complexes. The catalytic activity and selectivity of the reported vanadium complexes, copper salts and non-metal system 1-5 on non-volatile organosolv (NVO) lignin was investigated under basic condition. Details of the depolymerisation of lignin were determined by using Gel Permeation Chromatography (GPC) and the two-dimensional NMR technique, quantitative HSQC (q-HSQC) spectroscopy. Vanadium [2] and copper systems were found to be the most active for depolymerization of NVO lignin.
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Dumoulin, Audrey. "Synthèse asymétrique de 1,2-diamines et développement de nouveaux organoiodanes chiraux pour des réactions d'oxygénation." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS364.
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Les 1,2-diamines sont présentes dans de nombreux produits biologiquement actifs, ce qui a poussé les chimistes organiciens à développer de nouvelles voies d’accès à ces motifs. Dans ce contexte, la maitrise de leur stéréochimie est essentielle puisque leur activité biologique en découle. Afin de répondre à cette problématique, nous nous sommes intéressés au développement d’une réaction d’amination électrophile de dérivés d’énamides catalysée par des acides phosphoriques chiraux. Ces catalyseurs interagissent avec les substrats via des liaisons hydrogènes permettant d’activer simultanément un nucléophile et un électrophile. Notre stratégie s’est révélée très efficace et a permis de synthétiser une gamme de 1,2-diamines extrêmement variée. De nombreux motifs d’intérêt biologique, incorporant notamment des hétérocycles, très employés en chimie pharmaceutique et cosmétique, ont été compatibles avec ce procédé. Dans un second projet, nous nous sommes intéressés au design de composés d’iode hypervalent chiraux. Ces composés ont connu un essor considérable ces dernières années en raison de leur stabilité à l’air et à l’humidité, leur faible toxicité et leur réactivité intéressante. Cependant, malgré ces développements, l’exploitation des dérivés d’iode hypervalent dans des versions catalytiques asymétriques mériterait d’être plus amplement étudiée. Dans ce contexte, de nouveaux précatalyseurs ont été élaborés au laboratoire puis employés dans des réactions d’oxygénations énantiosélectives. La structure particulière de ces composés a permis d’obtenir les meilleurs excès énantiomériques de la littérature à ce jourThe 1,2- diamines can be found in many biologically active compounds, which pushed organic chemists to develop new methodologies to synthesize those molecules. In this context, the stereochemistry is essential because the biological activity ensues. Thus, we were interested in developing an enantioselective amination of enamide derivatives catalyzed by chiral phosphoric acids. These catalysts interact with substrates via hydrogen bonds to activate a nucleophile and an electrophile simultaneously. Our strategy proved to be very effective and allowed us to synthesize a wide range of 1,2- diamine. Many compounds of biological interest, including heterocycles used in pharmaceutical and cosmetic industry, were tolerated with this process. In another project, we looked at the design of chiral hypervalent iodine compounds. These compounds have recently gained considerable attention because of their stability to air and moisture, their low toxicity and their interesting reactivity. However, despite considerable development, the use of hypervalent iodine derivatives in catalytic asymmetric reactions deserves to be further studied. In this context, new pre-catalysts were developed in our laboratory and used in enantioselective oxygenation reactions. The special structure of these compounds yielded the best enantiomeric excesses of the literature to date
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Wloch, Morgan. "Synthèse totale de la (+)-strépantibine A, un ortho-quinol d’origine bactérienne, par désaromatisation hydroxylante phénolique asymétrique médiée par des iodanes-λ5 de type iodylarène." Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0035.
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La (+)-strépantibine A est un ortho-quinol (i.e., 6-alkyl-6-hydroxycyclohexa-2,4-diénone) qui a récemment été isolé à partir d’une bactérie du genre Streptomyces en association symbiotique avec les larves de la guêpe maçonne Sceliphron madraspatanum. Ce métabolite possède une activité inhibitrice prometteuse contre l'hexokinase 2, une enzyme responsable de la croissance tumorale. Parmi les nombreuses transformations chimiques qui permettent la formation d'ortho-quinols, la désaromatisation hydroxylante de phénols à l’aide d’agents de transfert d’atome d’oxygène à base de composés iodés hypervalents de type iodylarène (i.e., ArIO2) est une réaction développée dans notre laboratoire. Dans ce contexte, nous avons mis au point une réaction régio- et énantiocontrôlée en utilisant une nouvelle classe d’iodylarènes chiraux de structure pipérazinique. Cette innovation méthodologique nous a permis d’accomplir la première synthèse totale de la (+)-strépantibine A en neuf étapes avec un rendement global de 6%(+)-strepantibin A is an ortho-quinol (i.e., 6-alkyl-6-hydroxycyclohexa-2,4-dienone), which was recently isolated from a Streptomyces bacteria associated with the larvae of the mud dauber wasp Sceliphron madraspatanum. Promising in vitro inhibitory activity of this natural ortho-quinol was found against hexokinase 2, an enzyme responsible for tumor growth. Among many existing chemical transformations that allow the formation of ortho-quinols, hydroxylative phenol dearomatization using hypervalent iodine-based oxygen-atom transfer reagents, such as iodylarenes (i.e., ArIO2), is a reaction developed in our laboratory. In this context, we have set up a regio- and enantiocontrolled reaction using a novel class of chiral piperazine-based iodylarenes. This methodological innovation has allowed us to accomplish the first total synthesis of (+)-strepantibin A in nine steps with an overall yield of 6%
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Walkinshaw, Andrew James. "New catalytic methods for chemical synthesis : copper-catalysed electrophilic cyclisations of alkynes using hypervalent iodine reagents." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708870.
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Phipps, Robert James. "Copper catalysis as a tool for developing novel and selective arylation reactions using hypervalent iodine reagents." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608863.
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Grayfer, Tatyana. "Synthèse totale de la mallotojaponine C et bromofonctionnalisations de polyprénoïdes initiées par l'iode(III) hypervalent." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS349/document.
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Le paludisme est une maladie parasitaire qui présente une problématique de santé majeure, touchant actuellement plus de 200 millions de personnes dans le monde. Le développement de nouveaux médicaments est nécessaire pour succéder aux traitements existants qui perdent progressivement leur efficacité suite à l’émergence des résistances. Les produits naturels constituent une source d’inspiration inépuisable pour la recherche de nouveaux médicaments. Dans le cadre de cette thèse, nous nous sommes intéressés à deux familles de produits à propriétés antipaludiques : les mallotojaponines et les bromophycolides. Dans la première partie du projet, nous avons effectué la première synthèse totale de la mallotojaponine C. Nous avons également synthétisé une bibliothèque de ses analogues. Tous ces composés ont été testés contre Plasmodium falciparum responsable du paludisme et contre Trypanosoma brucei responsable de la maladie du sommeil. Nous avons confirmé l’activité antipaludique des mallotojaponines et découvert leur activité trypanocide. Dans la deuxième partie de ce projet, nous avons mis au point une méthode sélective et chimiodivergente de bromation des terpènes qui pourrait ensuite être appliquée à la synthèse des bromophycolides. En utilisant des réactifs d’iode(III) hypervalent pour générer des espèces bromonium électrophiles in situ à partir des bromures, nous avons réussi à mettre au point des conditions de bromocarbocyclisation, d’oxybromation et de dibromation des chaînes terpéniques. Dans tous les cas, les réactions sont rapides et faciles à mettre en œuvreMalaria is a parasitic disease affecting more than 200 million people in the world. The development of new antimalarial drugs is necessary in order to replace the existing treatments that are progressively becoming less efficient due to resistance phenomena. Natural products are an inexhaustible source of inspiration for the discovery of new drugs. In this project, we focused our attention on two natural products families exhibiting antimalarial properties: mallotojaponins and bromophycolides. In the first part of this project, we carried out the first total synthesis of mallotoajaponin C. We also synthesised a library of its analogues. All of these compounds were tested against Plasmodium falciparum responsible for malaria and against Trypanosoma brucei responsible for African sleeping sickness. We have confirmed the antimalarial activity of mallotojaponins and discovered their trypanocidal activity. In the second part of the project, we developed a chemodivergent and selective method of bromination of terpenes that could later be applied to the synthesis of bromophycolides. Using simple bromides and hypervalent iodine(III) reagents to generate electrophilic bromonium species in situ, we have shown that the reaction can be steered selectively towards the bromocarbocyclisation, the oxybromination or the dibromination of terpene chains. In all cases, the reactions are fast and easy to perform
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Soulard, Marine. "Approche synthétique vers la synthèse totale de l’epicocconone, étude de la réaction de désaromatisation oxydante à l’aide d’iode hypervalent (III) ou (V)." Thesis, Rouen, INSA, 2014. http://www.theses.fr/2014ISAM0005/document.
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L'epicocconone est un produit naturel tricyclique, de la famille des azaphilones, isolé en 2003 d'un champignon Epicoccum nigrum. Ce composé se lie de façon covalente aux amines, conduisant à la formation d'une énamine fluorescente. Cette réaction, réversible en fonction du pH, fait de ce composé un excellent marqueur de protéines pour la détection sur gels d'électrophorèse compatible avec une analyse de spectrométrie de masse. La synthèse de ce produit naturel a été débutée au sein de notre laboratoire en s'appuyant sur les travaux réalisés précédemment et mettant en jeu une étape clé de désaromatisation oxydante à l'aide d'iode hypervalent. Une étude méthodologique de réaction clé a permis de comparer l'efficacité et la diastéréosélectivité de l'oxydation effectuée par l'iode (III) ou l'iode (V)Epicocconone is a tricyclic natural product of the azaphilone family, isolated from the fungus Epicoccum nigrum. This compound covalently binds to primary amines, leading to a protein conjugate which is highly fluorescent. This reaction, reversible according to the pH, make this compound an excellent protein stain compatible with mass spectrometry analysis. The synthesis of this natural product has been started in our laboratory based on the previous work in involves a key oxidative dearomatization using hypervalent iodine. Methodological studies of this key reaction allowed us to compare the efficiency and diastereoselectivity of iodine (III) and iodine (V) mediated oxidations
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Sharma, Jhanvi. "DEVELOPMENT OF NEW HYPERVALENT IODINE MEDIATED REACTION METHODOLOGIES FOR CLEAVAGE OF ALKENES AND SYNTHESIS OF 1,2,4-OXADIAZOLES." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/theses/1376.
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The first part of thesis describes the synthesis of carbonyl compounds from the styrene and derivatives using [hydroxy(tosyloxy)iodo]benzene, a hypervalent iodine compound, and p-toluenesulfonic acid monohydrate. Four equivalents of hypervalent iodine reagent was necessary to provide the products in high yields. The reaction was performed at 70 °C under argon to avoid further oxidation of benzaldehyde to carboxylic acid. Electron rich styrenes were converted into benzaldehydes in good to high yield, whereas electron deficient styrenes produced bis(tosylates) as the major products. Three paths were possible for the high yield of aldehydes (i) cleavage of glycol intermediate; (ii) cleavage of the epoxide intermediate; (iii) further oxidative cleavage of the rearrangement product - phenylacetaldehydes. The second part of the thesis describes the synthesis of substituted 1,2,4-oxadiazoles from aldoximes. Hypervalent iodine was used at stoichiometric and catalytic level to synthesize 1,2,4-oxadiazoles. The reaction was believed to proceed through nitrile oxide as an intermediate, followed by 1,3-dipolar cycloaddition with nitriles. Moderate yield was obtained when benzonitrile was used, whereas poor yield was obtained with acetonitrile. The possible reason for moderate yield was mainly attributed to two factors: (i) elimination of water molecule from aldoximes; (ii) diastereomeric purity of aldoxime. The study is in preliminary stage and requires further investigation.
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Nasrallah, Ali. "Complexe de Rhodium(II) et iode hypervalent en catalyse : époxydation d’alcènes et amination de liaisons C(sp³)-H." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS427.
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Cette thèse a pour but de développer de nouveaux procédés catalytiques en combinant de réactifs de l’iode hypervalent avec des complexes de rhodium(II).Le premier chapitre concerne l’observation de l’époxyde comme produit secondaire inatendu dans les conditions de transfert de nitrène catalytique, et le développement d’une nouvelle méthode de préparation d’époxydes qui combine un réactif de l’iode hypervalent(III) et un complexe de dirhodium(II). Le second chapitre vise le développement d’une méthode d’amination C(sp³)–H benzylique intermoléculaire énantiosélective,en utilisant un nouveau complexe de rhodium chiral et un nouveau sulfamate benzylique et l’application de cette méthode à grande échelle et sur des produits complexes.Le dernier chapitre du manuscrit décrit une réaction d’amination régiosélective de liaisons C(sp³)–H non activées d’alcanes par catalyse au rhodium (II), en utilisant une quantité stoechiométrique d’alcanes comme substratsThis thesis describes the development of new catalytic processes by combining hypervalent iodine reagents with rhodium (II) complexes.The first chapter concerns the observation of the epoxide as a unexpected product under catalytic nitrene transfer conditions, and the development of a new method to promote the epoxidation of alkenes by combining a reagent of hypervalent iodine (III) and a complex of dirhodium (II).The second chapter is centered on the development of a general method forasymmetric intermolecular benzylic C(sp³)–H amination by combining a chiral rhodium (II) catalyst and a benzyl sulfamate, and the application of this method on large scale.The third part of this work show the development of a regioselective C(sp³)–H amination of unactivated alkane by rhodium (II) catalysis, using a stoichiometric amount of alkane as the substrate
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Walters, Jennifer Caroll. "NITROGEN-LIGATED (POLY)CATIONIC IODINE(III) REAGENTS: PLATFORMS FOR REAGENT DEVELOPMENT AND DIVERSE HETEROCYCLIC SYNTHESES." Diss., Temple University Libraries, 2019. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/558365.
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ChemistryPh.D.
Hypervalent iodine (HVI) reagents are easily accessed, highly tunable, mild, selective oxidants that are less toxic and more environmentally benign compared to their heavy metal counterparts. λ3-Iodanes, which possess an iodine center bound to one aryl substituent and two heteroatom ligands, have been the subject of recent interest due to their electrophilicity and hypernucleofugality. A central focus of the Wengryniuk laboratory has been the further development and application of a class of electrostatically activated (bis)cationic nitrogen-ligated HVI (N-HVI) reagents. N-HVIs feature datively bound heterocyclic ligands which results in dramatically enhanced electrophilicity and redox potentials. Despite being a highly tunable platform for reagent development, N-HVIs remain a relatively underexplored class of λ3-iodanes. This dissertation focuses on demonstrating N-HVI’s synthetic potential and developing novel variants to enhance their synthetic utility. Chapter 1 of this dissertation serves as a general background and introduction to nitrogen-ligated HVI reagents. Chapter 2 outlines our efforts in N-HVI library expansion, novel syntheses, and characterization. With a library of 33 novel N-HVIs in hand, ligand effects on N-HVI reactivity were analyzed via qualitative and quantitative methods. Chapter 3 describes our first synthetic application of N-HVIs in the development of novel oxidative rearrangements of simple and complex cyclic alcohols. This chapter describes the chemoselective ring expansion of 2° and 3° cyclic alcohols accessing medium-sized cyclic acetal products in good to excellent yields with applicability to Complexity-to-Diversity (CTD) efforts. Chapter 4 demonstrates our initial efforts toward the development of another synthetic method where the functionalized N-heterocyclic ligands of the N-HVIs can be regioselectivity incorporated into a molecule following N-HVI activation of an olefin. The pyridinium lactone salts formed from olefinic acids were isolated in excellent yields via simple trituration, supplying a synthetically useful functional handle that was easily derivatized via known methods. These four chapters summarize the current state of the research with nitrogen-ligated HVI salts, expand upon our initial publications to highlight the development of novel heterocyclic syntheses, and provide a useful guide to further explore the reactivity of these tunable reagents.
Temple University--Theses
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Kasahara, Takahito. "Applications of hypervalent iodine reagents in organic synthesis : the development of iodonium metathesis reaction and effort towards himandrine." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/55101.
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This thesis discloses two different applications of hypervalent iodine(III) reagents in organic synthesis. In the first part, a novel reactivity of diaryliodonium triflates towards aryl iodides will be discussed. The new mode of reactivity allows various diaryliodonium triflates to be accessed, simply by heating a mixture of electron deficient diaryliodonium triflate with a moderately electron rich aryliodide. In the second part of the thesis, the use of (diacetoxyiodo) benzene in oxidative amidation in the context of total synthesis will be made.Science, Faculty of
Chemistry, Department of
Graduate
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Lukamto, Daniel Hartoyo. "Applications of hypervalent iodine reagents : from enantioselective copper-catalysed arylation-semipinacol cascade to methionine functionalisation for peptide macrocyclisation." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/283560.
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The unifying theme of this thesis is the exploitation of the reactivity of aryliodonium salts as electrophile transfer reagents. In the first part of the thesis, diaryliodonium salts are employed as arylation reagents for the enantioselective copper-catalysed arylative semipinacol rearrangement (SPR) of various tertiary allylic alcohols. This cascade reaction is a rare example of asymmetrically activating SPR using carbon electrophiles. Different substrate classes - including dihydropyran, indene and dihydronaphthalene moieties - are converted to enantioenriched beta-aryl spirocyclic ketones in excellent yields and enantioselectivities, and often as a single diastereomer. These are in turn useful functional handles for transformations into other moieties, including further rearrangements via Baeyer-Villiger oxidation. In the second part of this thesis, a two-step process for the macrocyclisation of native peptides via a non-natural linkage is developed. This study exploits previous work conducted in the group on the use of aryliodonium salts as methionine-selective diazoacetate transfer reagents. The functionalised methionine is in turn used for an intramolecular rhodium-catalysed insertion into tryptophan. Eventual translation onto solid-phase enables facile access into various macrocyclic peptides.
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Bosnidou, Alexandra Eleni. "New Methodology for C-N Bond Formation within Iodine Redox Manifolds." Doctoral thesis, Universitat Rovira i Virgili, 2019. http://hdl.handle.net/10803/668478.
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Els últims desenvolupaments en el camp de la construcció d’enllaços carboni-nitrogen es mostren en aquesta tesi doctoral. En aquesta, es revelen alternatives més verdes a les metodologies sintètiques comunes, amb l’ús de reactius de iode hipervalent i iode molecular com a principals promotors.
Inicialment, es presenta l’ús de reactius de iode hipervalent definits que promouen l’aminació C-H selectiva i directa del nucli indol de diferents tipus de triptamines. Començant per l’aminació general, transformacions posteriors, com la iodació, fluoració, etc. es van realitzar per tal de rendir productes més funcionalitzats, amb una quimioselectivitat remarcablement alta. Per tant, s’ha fet disponible un major grau de diversificació estructural per als derivats triptamínics, proveint blocs de construcció (building blocks) que obren espai químic per a més exploració.
Seguidament, es discuteix l’aminació catalítica fotoquímica d’arens. La reacció es dóna en catàlisi de iode i presència de llum visible com a iniciador, i permet l’accés a un ventall d’aril amines substituïdes. L’ampli abast de la reacció es va poder expandir encara més a derivats bloquejats amb grups silil, que experimenten una aminació intramolecular per tal de donar lloc a heterocicles de set membres. L’escissió del grup silil permet l’accés a les corresponents anilines 3-substituïdes.
L’aminació directa d’enllaços C-H alifàtics ha estat una de les transformacions més desafiants en la química orgànica. En la última part de la tesi, reportem l’esmunyedissa aminació C(sp3)-H sota un sistema catalític únic, basat en la recentment desenvolupada aminació intramolecular. Aquesta estratègia sintètica pràctica permet l’accés a blocs de construcció aminats. És presentada també una extensió que fomenta múltiples aminacions C-H per a aconseguir heterocicles aminats. La utilitat sintètica de la metodologia és demostrada per la síntesi de quatre productes farmacèutics rellevants.En esta Tesis Doctoral se describen los últimos avances en el campo de la construcción de enlaces carbono-nitrógeno. En ella se discuten alternativas más verdes, comparadas con las metodologías más comunes, mediante el uso de reactivos hipervalentes de yodo y yodo molecular como principales promotores. En la primera sección se presenta el uso de reactivos hipervalentes de yodo que promueven la aminacion C-H directa y selectiva del grupo indol en varios derivados de triptamina. A partir de esta aminación general, otras transformaciones, tales como iodinación, fluorinación, etc. fueron llevadas a cabo, obteniendo productos altamente funcionalizados con una remarcable alta quimioselectividad. De este modo, una alta diversificación estructural de derivados de triptamina están disponibles, proveyendo diferentes componentes que permiten futuras exploraciones en este área. En la siguiente sección, se describe la aminación fotoquímica y catalítica de arenos. Esta reacción funciona mediante catálisis de yodo molecular en presencia de luz visible como iniciador, dando acceso a un amplio rango de arilaminas con diferentes patrones de substitución. Esta metodología es muy general y puede expandirse a derivados con silicio que dan lugar a heterociclos de siete miembros. La ruptura de este enlace silicio-carbono da acceso a las correspondientes anilinas meta-subtituidas. La aminación directa de enlaces C-H alifáticos es una de las transformaciones más dificiles de conseguir en química orgánica. En la última parte de esta Tesis se describe la aminación intermolecular de C(sp3)-H basada en la recientemente desarrollada versión intramolecular. Esta estrategia sintética permite el acceso a diferentes estructuras aminadas de importancia. También se presenta la extensión de esta metodología hacia la aminacion de multiples C-H, obteniendo aza-heterociclos. La utilidad práctica de esta metodología esta demostrada mediante la síntesis de cuatro compuestos de interés farmacéutico
The latest developments in the field of oxidative carbon-nitrogen bond construction are represented in this Doctoral Thesis. Greener alternatives to established synthetic methodologies have been disclosed with the use of hypervalent iodine reagents and molecular iodine as main promoters. Initially, the use of defined hypervalent iodine reagents that promote the selective direct C-H-amination at the indole core of various tryptamines is presented. Starting from the general amination, subsequent transformations, such as iodination, fluorination etc. were performed to afford higher-functionalized products with a noteworthy chemoselectivity. Consequently, a higher degree of structural diversification has become available for tryptamine derivatives, providing building blocks that open chemical space for further exploration. Subsequently, a photochemical catalytic amination of arenes is discussed. The reaction proceeds under benign iodine catalysis in the presence of visible light as the initiator and provides access to a range of differently substituted arylamines. The broad scope of the reaction could further be expanded to silyl-tethered derivatives, which undergo intramolecular amination to give rise to seven-membered heterocycles. Cleavage of the silicon tether provides access to the corresponding 3-substitued anilines. The direct amination of aliphatic C-H bonds has remained one of the most challenging transformations in organic chemistry. In the last part of this thesis, the elusive intermolecular C(sp3)-H amination based on a unique homogeneous iodine catalyst system is reported. This practical synthetic strategy allows the access to aminated building blocks. An extension that fosters innovative multiple C-H amination toward aminated heterocycles is also presented. The synthetic utility of the methodology is demonstrated by the synthesis of four relevant pharmaceuticals.
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Gelis, Coralie. "Développement de réactions énantiosélectives organocatalysées pour la synthèse de molécules cycliques énantioenrichies." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS430.
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Le développement de méthodes de synthèse asymétrique est très important pour l’accès à des molécules à visées thérapeutiques. Dans ce contexte, nous nous sommes intéressés à l’utilisation d’organocatalyseurs chiraux pour la synthèse de molécules cycliques énantioenrichies. Dans une première partie sont présentées des réactions de cycloadditions formelles (3+2), (4+2) et (4+3) à partir d’ènecarbamates ou de diènecarbamates catalysées par des acides phosphoriques chiraux. Ces derniers étant bifonctionnel, ils permettent l’activation des deux partenaires de cycloaddition menant à la synthèse d’indolines, de 2,3-dihydrobenzofuranes, de benzoquinones carbonannulées, de cyclohepta[b]indoles et de tétrahydroquinolines de façon hautement stéréosélective. Dans une seconde partie, nous nous sommes intéressés à l’utilisation de composés d’iode hypervalent chiraux comme organocatalyseurs. En effet, ces composés présentent une réactivité intéressante tout en étant stable et faiblement toxique. Ainsi, leur utilisation dans une réaction de lactonisation à partir de substrats flexibles a permis l’obtention de divers hétérocycles avec de bons résultatsThe development of new enantioselective methodologies is essential for the synthesis of bioactive compounds. In this context, we were interested in using organocatalysts for the synthesis of enantioenriched cyclic molecules. In a first part will be describe chiral phosphoric acid catalyzed (3+2), (4+2) and (4+3) formal cycloadditions using enecarbamate or dienecarbamate. These catalysts are bifunctional and can interact with both cycloaddition partners leading to the synthesis of 2,3-dihydrobenzofuranes, carboannulated benzoquinones, cyclohepta[b]indoles and tetrahydroquinolines with high stereocontrol. In a second phase, we were interested in using chiral hypervalent iodine as organocatalyst. Theses compounds present interesting reactivity while being stable and not very toxic. Their use permits us to develop a lactonisation starting from flexible substrate and led to the synthesis of various heterocycles with good results
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Dequirez, Geoffroy. "Transferts de nitrène catalysés par les métaux de transition. Développement de nouvelles réactions pour la difonctionnalisation d’alcènes et application en synthèse." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112256/document.
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Cette thèse décrit le développement de nouvelles réactions de difonctionnalisation catalytique d’oléfines impliquant des transferts de nitrène médiés par des complexes de dirhodium(II).La première partie de ce manuscrit s’articule autour de la réactivité d’alcènes riches en électrons, c’est-à-dire substitués par un hétéroatome. L’application des conditions de transfert de nitrène catalytiques a permis la fonctionnalisation oxydante des positions C2 et C3 de l’indole. En utilisant cette stratégie, il est donc possible d’effectuer formellement des réactions d’oxyamination intermoléculaire et de diamination intramoléculaire. Dans ce dernier cas, le motif indoline formé étant présent dans certains produits naturels, la synthèse totale de la Pestalazine B a pu être initiée. Le champ d’application de ces réactions a été étendu aux énamides en collaboration avec le groupe du Professeur Isabelle Gillaizeau.La seconde partie de ce travail concerne le développement de la réaction d’oxyamination d’oléfines aromatiques et aliphatiques. Le champ d’application de cette réaction a été étudié en détail tandis que des expériences témoins et des analyses RMN ont permis de proposer un mécanisme original.Enfin, dans un dernier temps, nous avons démontré que par extension du concept, l’application des transferts de nitrène catalytiques permet de réaliser des réactions de diamination intermoléculaire d’oléfinesThis manuscript describes the development of new reactions for the difunctionalization of alkenes that involve dirhodium(II)-catalyzed nitrene transfers.The first part of the studies focuses on the reactivity of electron-rich alkenes, i.e. substituted by a heteroatom. The application of catalytic nitrene transfers has led to the development of oxidative conditions for the difunctionalization of the 2,3-π-bond of indolic derivatives. The strategy, thus, has allowed to perform formal reactions of intermolecular oxyamination and intramolecular diamination. The latter gives access to indoline skeleton found in the structure of several natural products such as Pestalazine B, the total synthesis of which has been initiated. The scope of intermolecular oxyamination has then been extended successfully to enamides in collaboration with the group of Professor Isabelle Gillaizeau.The second part of the experimental work has been aimed at applying the catalytic oxyamination to aromatic and aliphatic alkenes. The scope of the reaction has been extensively studied while test experiments and NMR analysis have allowed to propose an unexpected mechanism based on the Lewis acid character of the metallanitrene.Finally, the scope of catalytic nitrene transfers has been extended to the intermolecular diamination of alkenes with the development of bis(arenesulfonyl)imide-type reagents
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Stridfeldt, Elin. "Hypervalent Iodine Reagents in Metal-Free Arylations and Vinylations : Investigation of Suitable Coupling Partners and Synthesis of New Reagents." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-141580.
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This thesis concerns the development of metal-free reactions to obtain carbon-heteroatom and carbon-carbon bonds. This is achieved by transferring carbon ligands from hypervalent iodine reagents to suitable nucleophiles. The bulk of the work presented herein concerns arylation of oxygen and nitrogen nucleophiles, using the well-known diaryliodonium salts as aryl sources. In the first project, O-arylation of the oxime ethyl acetohydroxamate was studied. It was found that electron-poor as well as electron-rich aryl moieties could be transferred successfully to this nucleophile. Furthermore, the protocol could be extended to a sequential one-pot synthesis of benzo[b]furans. This method allowed for a fast synthesis of the natural product stemofuran A and formal syntheses of other natural products. In a successive project, O-arylation of hydroxide and aliphatic alkoxides was investigated. It is known that electron-poor aryl moieties can be transferred to these nucleophiles in moderate to high yields. However, combined with more electron-rich diaryliodonium salts, a large amount of side products were formed. These were suppressed upon addition of aryne traps, suggesting that aryne pathways are competing with the desired ligand coupling. It was also observed that secondary alcohols were oxidized to the corresponding ketones. The mechanism for this oxidation was investigated and aryne pathways could be excluded. Instead we suggest that the carbinol hydrogen gets deprotonated via an internal mechanism, after the alkoxide has coordinated to the iodonium salt. Highly sterically congested alkyl aryl ethers could be obtained in high yields by combining tertiary alcohols with ortho-blocked diaryliodonium salts. Next, N-arylation of secondary acyclic amides was studied using acetanilide as the model substrate. This procedure was suitable for transfer of electron-poor as well as ortho-substituted aryl moieties, but attempts to transfer very electron-rich aryl groups were unsuccessful. On the other hand, the amides displayed a complementary reactivity, allowing phenylation of electron-rich amides. In the final project, a one-pot synthesis of the cyclic iodonium reagent vinylbenziodoxolone is presented. These compounds have not been explored as reagents earlier. Initial screenings showed that the vinyl moiety could be transferred to nitrocyclohexane with opposite regioselectivity compared to the acyclic analogue of the reagent.At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Manuscript.
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Coffinier, Romain. "Nouveaux iodanes chiraux pour des réactions d’oxygénation asymétriques." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14974/document.
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Ces travaux concernent le développement de nouveaux iodanes chiraux et leur application à des réactions d’oxygénation asymétriques. Ces réactifs à base d’iode hypervalent constituent une alternative intéressante aux réactifs à base de métaux lourds en termes de réactivité et de toxicité. La première partie de ce travail a été consacrée à la synthèse de nouvelles structures originales C 2 -symétriques énantiopures de type S alen. Un criblage de conditions oxydantes a ensuite montré que seul le 3,3-diméthyldioxirane (DMDO) permet une oxydation propre et sélective de ces iodoarènes en iodanes-λ5 correspondants, composés isolables par simple filtration et dont la nature a pu être déterminée sans ambiguïté par analyse spectroscopique RMN 13C. Dans un second temps, ces nouveaux iodanes-λ5 chiraux ont été appliqués à des réactions d’oxygénation asymétriques, et plus particulièrement à la désaromatisation hydroxylante (réaction HPD) de 2-alkylphénols tels que le carvacrol et le thymol. Les meilleurs excès énantiomériques (ee) sont obtenus lorsque la réaction HPD est réalisée à température ambiante dans un mélange 85:15 de dichlorométhane/ trifluoroéthanol. Le carvacrol est ainsi converti en son cyclodimère [4+2] d’ortho -quinol naturel, le biscarvacrol, avec 55% de ee, et le thymol en bisthymol avec 68% de eeThis work focuses on the development of new chiral iodanes and their application to asymmetric oxygenation reactions. These hypervalent iodine-based reagents represent an interesting alternative to heavy metal-based reagents in terms of reactivity and toxicity. The first part of this work consisted in the synthesis of new enantiopure C 2 -symmetrical Salen-type structures. A screening of oxidizing conditions then showed that only 3,3-dimethyldioxirane (DMDO) is able to mediate a clean and selective oxidation of these iodoarenes into to the corresponding λ5-iodanes, which were isolated by simple filtration and further characterized by 13C NMR spectroscopic analysis. In a second part, these new chiral λ5-iodanes were applied to asymmetric oxygenation reactions, in particular the Hydroxylative Phenol Dearomatization reaction (HPD reaction) of 2-alkylphenols such as carvacrol and thymol. Best enantiomeric excesses (ee) where obtained when the HPD reaction was performed in a 85:15 mixture of dichloromethane/ trifluoroethanol. Carvacrol was converted into its natural ortho -quinol-based [4+2] cyclodimer biscarvacrol with ee up to 55%, and thymol into bisthymol with ee up to 68%
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Bosset, Cyril. "Synthèse d’iodanes biaryliques chiraux : application à des réactions d’oxygénation asymétrique." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14983/document.
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La chimie des dérivés à base d’iode hypervalent, également appelés iodanes, connaît depuis la fin des années 1990 un essor important qui s’explique par leurs conditions d’utilisation douces et leur faible toxicité comparée à celle des réactifs à base de métaux lourds. Plus récemment, des versions chirales de ces réactifs font l’objet de nombreuses recherches. Dans ce contexte, une première partie de ces travaux de thèse a consisté à développer de nouveaux iodanes chiraux basés sur un squelette biarylique atropoiso-mériquement pur de type soit 1,1’-binaphtyle, soit 5,5’,6,6’,7,7’,8,8’-octahydro-1,1’-binaphtyle. Plusieurs iodobiaryles ont été synthétisés, puis oxydés efficacement et sélectivement au 3,3-diméthyldioxirane (DMDO) pour donner, après une simple filtration, les iodanes correspondants purs. Le degré d’oxydation de l’atome d’iode de chacun de ces composés a été déterminé par spectroscopie RMN 13C : des iodanes-λ3 ont été isolés dans le cas des systèmes binaphtyliques ou substitués par une fonction acide carboxylique en ortho de l’atome d’iode, tandis que des iodanes-λ5 ont été obtenus pour les composés basés sur un squelette octahydro-1,1’-binaphtyle. Dans une seconde partie, ces iodanes ont été appliqués à des réactions d’oxygénation et plus particulièrement à la désaromatisation hydroxylante asymétrique de 2-alkylarénols. Le 2-méthylnaphtol a été converti en son ortho-quinol avec un excès énantiomérique (ee) atteignant 73 %. Des phénols naturels comme le carvacrol et le thymol ont conduit aux cyclodimères [4+2] d’ortho-quinols, le biscarvacrol et le bisthymol, avec des résultats encore meilleurs, respectivement 74 % ee et 94 % eeThe chemistry of hypervalent organoiodine compounds, also referred to as iodanes, has experienced an impressive development since the 1990s due to their mild oxidizing conditions and their low toxicity compared to heavy metal-based reagents. Recently, chiral versions of iodanes have been focusing several research efforts. In this context, the first part of this work was dedicated to the development of new chiral iodanes with an atropisomerically pure biarylic structure, either 1,1’-binaphthyl or 5,5’,6,6’,7,7’,8,8’-octahydro-1,1’-binaphthyl. Many iodobiaryls were synthesized, and then efficiently and selectively oxidized with 3,3-dimethyldioxirane (DMDO) to furnish the corresponding pure iodanes by simple filtration. The oxidation state of the iodine atom of each compound was determined by 13C NMR spectroscopic analysis: λ3-iodanes were isolated in the case of binaphthylic structures or when the iodoarene bears a carboxylic acid function ortho to the iodine atom, whereas λ5-iodanes were obtained for octahydro-1,1’-binaphthylic compounds. These iodanes were next applied to oxygenation reactions and in particular to asymmetric hydroxylative dearomatization of 2-alkylarenols. 2-Methylnaphthol was converted into its ortho-quinol with up to 73 % enantiomeric excess (ee). Natural phenols such as carvacrol and thymol gave the corresponding ortho-quinol-based [4+2] cyclodimers, biscarvacrol and bisthymol, with even better results of 74 % ee and 94 % ee, respectively