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Dissertations / Theses on the topic 'N–H bond cleavage'
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1
Chang, Yunghung. "Studies on PNP-Pincer Type Phosphaalkene Complexes of Iridium." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/189364.
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Hughes, Deborah. "N-N bond cleavage : an approach to slaframine." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277217.
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Baum, Marc Michael. "Cleavage of the N-N bond in high valent molybdenum hydrazido complexes." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46668.
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Berg, Tieme Adriaan van den. "Iron catalyzed oxidation chemistry from C-H bond activation to DNA cleavage /." [S.l. : [Groningen : s.n.] ; University of Groningen] [Host], 2008. http://irs.ub.rug.nl/ppn/315029242.
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Locati, Abel Jean Serge. "Computational study of c-h bond cleavage and c-c bond formation processes catalyzed by transition metal complexes." Doctoral thesis, Universitat Rovira i Virgili, 2012. http://hdl.handle.net/10803/79120.
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La primera parte de la tesis se dedica al estudio del mecanismo de una reacción de activación C-H por un complejo de niobio. Se racionalizó el mecanismo de activación de enlaces C-H del benceno por el complejo TpMe2NbCH3(c-C3H5)(MeCCMe). El intermedio clave es un complejo inusual de 2-ciclopropeno. Conseguimos también racionalizar las selectividades obtenidas para la activación de varios alquilaromáticos por el complejo de niobio 2-ciclopropeno. También se investigó el papel del ligando alquino en estos complejos y su posible papel en procesos de migración de ligandos.
En la segunda parte de la tesis, se investigaron las reacciones de acoplamiento cruzado con reactivos basados en silicio. Los resultados sugieren que la transmetalación es más fácil después de la disociación de la fosfina, o cuando un ligando bromuro está coordinado al paladio. El efecto beneficioso de la dibencilidenoacetona en el acoplamiento también fue aclarado.The first part of the thesis is mainly devoted to the mechanism of a C-H activation reaction by a niobium complex. The mechanism of C-H bond activation of benzene by the TpMe2NbCH3-(c-C3H5)-(MeCCMe) complex was rationalized. The key intermediate is an unusual 2-cyclopropene complex. We rationalized the selectivities obtained for the activation of several alkylaromatics by the 2-cyclopropene niobium complex. The intriguing role of the alkyne ligand of the same complex, and its possible role in the migration processes, was investigated. In the second part of the thesis, we focused on the silicon based cross-coupling. The results suggest than the transmetalation is easier after phosphine dissociation, and in presence of the bromide ligand on the palladium. The beneficial effect of dibenzylideneacetone on the coupling was clarified.
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Laren, Martijn Wouter van. "Palladium-catalyzed C-H and C-N bond formation." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2004. http://dare.uva.nl/document/75422.
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Shimbayashi, Takuya. "Studies on Transition Metal-Mediated Transformation of Oxime Esters Triggered by N-O Bond Cleavage Directed toward Synthesis of N-Heterocyclic Compounds." Kyoto University, 2018. http://hdl.handle.net/2433/232053.
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Pearson, Stephen. "High oxidation state carbene complexes for C-H bond activation catalysis." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/7570.
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Chapter one is an introduction to the less common coordination and oxidation chemistry of palladium; complexes containing Pd-OR, Pd-NR2 and those in the oxidation states of +IV. An outline of PdII/IV catalysed ligand-directed oxidative functionalisation is also included. Chapter two covers the design and synthesis of a range of tethered N-heterocyclic carbene (NHC) complexes of Pd. In addition, the syntheses of a number of new tethered NHC ligands are described. The use of Density Functional Theory (DFT) to model the complexes in this thesis was explored. Chapter three describes the synthesis and characterisation of PdIV halide complexes. The relevance of these compounds to PdII/IV catalysed ligand-directed oxidative functionalisation is explored. DFT was used to probe the reaction pathway for N-bromosuccinimide and iodobenzene dichloride. Chapter four examines reactions with oxidants used to form C-O and C-C bonds. The reaction pathway for iodobenzene diacetate was investigated using DFT. Chapter five contains experimental details and characterising data for the compounds reported.
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Cheng, Hanchao Verfasser], Carsten [Akademischer Betreuer] [Bolm, and Dieter [Akademischer Betreuer] Enders. "Copper-Catalyzed N−H Functionalizations of NH-Sulfoximines for C−N Bond Formation / Hanchao Cheng ; Carsten Bolm, Dieter Enders." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/1162499672/34.
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Cheng, Hanchao [Verfasser], Carsten [Akademischer Betreuer] Bolm, and Dieter [Akademischer Betreuer] Enders. "Copper-Catalyzed N−H Functionalizations of NH-Sulfoximines for C−N Bond Formation / Hanchao Cheng ; Carsten Bolm, Dieter Enders." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/1162499672/34.
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Biafora, Agostino [Verfasser], and Lukas J. [Akademischer Betreuer] Gooßen. "Sustainable Methods for the Catalytic Regioselective Transformation of Aromatic Carboxylic Acids via C-COOH and C-H Bond Cleavage / Agostino Biafora ; Betreuer: Lukas J. Gooßen." Kaiserslautern : Technische Universität Kaiserslautern, 2017. http://d-nb.info/1140760912/34.
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Phillips, Nicholas Andrew. "N-heterocyclic carbene stabilisation of low valent metal centres for the activation of E-H bonds." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:144af4d6-3fb2-49d8-afbd-504a5cb40857.
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This thesis examines the effects of coordinating highly sterically demanding and strongly electron donating saturated N-heterocyclic carbenes (NHCs) at late transition metal centres. Chapter III details the synthesis of a range of iridium complexes of the type (NHC)2IrHxCly [x = 1, 2; y = 0, 1], bearing the saturated NHCs 5-Mes, 6-Mes and 7-Mes. Unusually facile activation chemistry is observed in the reaction of [Ir(COE)2Cl]2 with 6-Mes and 7-Mes to form the doubly cyclometallated species (6-Mes')2IrH and (7-Mes')2IrH, which were fully characterised. The responses of these complexes to the addition of dihydrogen and HCl were studied, leading to the controlled synthesis of range of precursors to 14-electron iridium cations. In Chapter IV the formation of low valent iridium cations with weakly coordinating anions is targeted. Isolation of the cationic complexes [(NHC)(NHC')IrH][BArf4] and [(NHC)2IrH2][BArf4] (NHC = 6-Mes, 7-Mes) showcases the stabilising power offered by these expanded ring systems. This allowed the study the interaction of these low valent species with a range of amine-borane substrates which are known to be readily dehydrogenated. Thermodynamic data on the C-H bond activation processes occurring at these iridium centres were able to be obtained due to facile, reversible oxidative addition of C-H bonds across the 14-electron iridium. Chapter V focuses on the effects of increasing the steric bulk of these NHCs to limit the coordination of multiple ligands at the metal centre. Use of 2,6-diisopropyl-phenyl (Dipp) groups on the expanded ring NHCs, instead of mesityl groups, leads to an unprecedented mode of reactivity with [Ir(COE)2Cl]2. Activation and cleavage of C-N bonds in the carbene ring is observed, resulting in an open chain ligand chelating to the metal centre. Activation of the backbone in this manner has allowed the synthesis of saturated NHCs bearing a weakly coordinating anion on the ring. Here the first example of an anionic, saturated NHC is reported. In Chapter VI these highly sterically demanding NHCs are exploited to stabilise active species in low valent gold chemistry. The extreme steric bulk of the 6-Dipp ligand disfavours reduction of Au(I) to Au(0), however the resulting cation is observed to interact strongly with the weakly coordinating anion, [BArf4]-. Thus, attempts were made to optimise the anion and conditions to isolate a catalytically relevant intermediate. The strong donating power of these expanded ring NHCs is also exploited to activate gold hydride complexes of the type (NHC)AuH (NHC = 6-Dipp, 7-Dipp). Analogues of [H3]+ containing gold atoms ([{LAu}2H]+ and [LAuH2]+) supported by expanded ring NHCs were also targeted.
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Raghuvanshi, Keshav. "Ruthenium(II)-Catalyzed C-N, C-O and C-C Formations by C-H Activation." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://hdl.handle.net/11858/00-1735-0000-002B-7D4C-2.
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Song, Weifeng. "Cobalt- and Nickel-Catalyzed Functionalization of Unactivated C–Hal, C–O and C–H Bonds." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2013. http://hdl.handle.net/11858/00-1735-0000-0001-BC70-0.
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Patil, Shradha Vasant. "Radical additions of hydrocarbons, ethers and acetals to alkenes via allyl transfer reaction: A new chain reaction for C-H bond functionalization." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/50658.
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Functionalization of hydrocarbons via a free-radical based allyl transfer reaction using various allyl bromide substrates has been previously studied. The work described in this dissertation focuses on the replacement of Br by phthalimido-N-oxyl (PINO ) which helps make this chemistry environmentally friendly. To replace Br with PINO , replacement of previously used allyl-bromide substrates with new allyl-PINO substrates were necessary. Various allyl- PINO compounds were synthesized and the use of these allyl-phthalimido-N-oxyl (allyl-PINO) compounds for the functionalization of various alkyl aromatic hydrocarbons is demonstrated.Kinetic studies were performed to observe the efficiency of the new chain reaction compared to the previously reported studies with allyl-bromides. We recently discovered that these allyl substrates are useful for the functionalization of ethers and acetals. The functionalization of various cyclic and acyclic ethers was performed using these allyl transfer reactions. This reaction was also performed in-solution, which allowed us to perform these reactions at low reagent concentrations. Kinetic chain lengths were measured for these reactions. High chain lengths were observed for all used ethers. Kinetic studies to investigate the rate of radical addition-elimination processes were performed using laser flash photolysis and competition kinetics. These experiments helped us to measure the reactivity and selectivity of PINO as a chain carrier in comparison with Br .
Additionally, a new competition experiment was designed to study the relative rate constant for
the -fragmentation process. For this experiment a novel substrate that contains two leaving
groups, Br and PINO , was synthesized, and the relative rates of elimination of Br vs PINO
were compared.
Ph. D.
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Brown, Adam Ross. "I. Engaging Cationic Intermediates in Asymmetric Catalysis: Enantioselective Reactions of Carbenium Ions and N,N-Dialkyliminium Ions II. Enantioselective Catalysis of the Cope-Type Hydroamination by H-Bond Donors." Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:11009.
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The research described here explores the ability of dual H-bond donor catalysts to induce asymmetry in a variety of synthetically useful transformations that proceed via diverse reactive intermediates. In Chapters 1-3, we investigate ureas and thioureas as anion-binding catalysts for asymmetric reactions that proceeed via cationic intermediates with little precedent as electrophiles in asymmetric catalysis. Chapter 4 details our application of H-bond donor catalysis to the Cope-type hydroamination. Chapter 1 describes the development of an asymmetric aldehyde alkylation catalyzed by a bifunctional primary aminothiourea. A variety of 2-aryl propionaldehydes are alkylated with benzhydryl bromides in moderate to good yields and good enantioselectivities. Catalyst structure-activity relationship studies of the alkylation pointed towards electrophile activation by the dual H-bond donor moiety. Experiments aimed at gaining a better understanding of the electophile activation mode and characterizing the activated electrophilic intermediate in the alkylation reaction are described in Chapter 2. The development of an enantioselective cyanide addition to N,N-dialkyliminium intermediates is the subject of Chapter 3. A variety of strategies for accessing N,N- dialkyliminium ions are established, and chiral thioureas are shown to promote the addition of cyanide to such intermediates with moderate enantioselectivities. Chapter 4 details our discovery that thioureas bearing polarizable and conformationally constrained aromatic groups catalyze highly enantioselective Cope-type hydroaminations. This powerful transformation provides a variety of chiral pyrrolidine products under mild reaction conditions.Chemistry and Chemical Biology
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So, Sonia. "Boronate Urea Activation of Nitro Compounds." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1395764122.
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Yang, Kaiyuan. "Substitution Chemistry of the Cobalt Complexes [Co₂(CO)₆(PhC≡CR) (R=Ph, H) and PhCCo₃(CO)₉] with the Diphosphine Ligands [Bis(diphenylphosphino)maleic Anhydride (BMA) and (Z)-Ph₂PCH=CHPPh₂]. Reversible Chelate-to-Bridge Diphosphine Ligand Exchange, Phosphorus-Carbon Bond Cleavage and Phosphorus-Carbon Bond Formation." Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc279206/.
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The tricobalt cluster PhCCo3(CO)9 (1) reacts with the bidentate phosphine ligand 2,3-bis(diphenylphosphino)maleic anhydride (bma) in the presence of added Me3NO to give the diphosphine-substituted cluster PhCCo3(CO)7(bma) (2). Cluster 2 is unstable in solution, readily losing CO to afford Co3(CO)6[(μ2-η2/η1-C(Ph)C=C(PPh2)C(O)OC(O)](μ2-PPh2) (3) as the sole observed product. VT-31P NMR measurements on cluster 2 indicate that the bma ligand functions as both a chelating and a bridging ligand. At -97 °C, 31P NMR analysis of 2 reveals a Keq of 5.7 in favor of the bridging isomer. The bridged bma cluster 2 is the only observed species above -50°C. The solid-state structure of 2 does not correspond to the major bridging isomer observed in solution but rather the minor chelating isomer. The conversion of 2 to 3 followed first-order kinetics, with the reaction rates being independent of the nature of the reaction solvent and strongly suppressed by added CO, supporting a dissociative loss of CO as the rate-determining step. The activation parameters for CO loss were determined to be ΔH≠ = 29.9 ± 2.2 kcal/mol and ΔS≠ = 21.6 ± 6 eu.
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Margalef, Pallarès Jèssica. "Screening of modular and readily available ligand libraries for C-X (X=H, C, N and O) bond forming reactions. The use of DFT studies for catalysts optimization." Doctoral thesis, Universitat Rovira i Virgili, 2016. http://hdl.handle.net/10803/386578.
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El creixent interès per a l’obtenció de compostos enantiomèricament purs, ha conduït a un important desenvolupament de la catàlisi asimètrica. En aquest context, aquesta tesis és centra en la síntesis de vàries famílies de lligands quirals altament modulars a partir de compostos de fàcil disponibilitat. Concretament, s'ha treballat en la síntesis de lligands fosfit-tioèter, fosfit-piridina, fosfit-triazola i lligands hidroaximida i tioamida. Tots ells tenen en comú que són sòlids, estables i per tant de fàcil manipulació. Aquests lligands s'han aplicat en la hidrogenació d’olefines funcionalitzades i no funcionalitzades catalitzada per Rh i Ir, en la reducció de cetones mitjançant transferència d’hidrogen catalitzada per Rh i Ru, en reaccions de substitució alílica catalitzada per Pd i en l'addició d'organoaluminats a aldehids catalitzada per Ni. A més a més, en alguns casos s'han realitzat estudis DFT per tal d'agilitzar el procés d'optimització dels lligands. Així doncs, s'ha aconseguit l'obtenció de diferents compostos químics quirals d'alt interès sintètic (alcohols, alcans funcionalitzats i no funcionalitzats, al·lils substituits) en grans enantioselectivitats i en el millor dels casos s'han aconseguit els productes en la seva forma enantiomèricament pura (>99% ee).El creciente interés para la obtención de compuestos enantioméricamente puros para la obtención de compuestos enantioméricamente puros, ha conducido a un importante desarrollo de la catálisis asimétrica. En este contexto, esta tesis se centra en la síntesis de varias familias de ligandos quirales altamente modulares a partir de compuestos de fácil disponibilidad. Concretamente, se ha trabajado en la síntesis de ligandos fosfito-tioéter, fosfito-piridina, fosfito-triazoles y ligandos hidroaximida y tioamida. Todos ellos tienen en común que son sólidos, estables y por lo tanto de fácil manipulación. Estos ligandos se han aplicado en la hidrogenación de olefinas funcionalizadas y no funcionalizadas catalizada por Rh e Ir, en la reducción de cetonas mediante transferencia de hidrógeno catalizada por Rh y Ru, en reacciones de sustitución alílica catalizada por Pd y en el adición de organoaluminiatos a aldehídos catalizada por Ni. Además, en algunos casos se han realizado estudios DFT para agilizar el proceso de optimización de los ligandos. Así pues, se ha logrado la obtención de diferentes compuestos químicos quirales de alto interés sintético (ej. alcoholes, alcanos funcionalizados y no funcionalizados, alilos sustituidos) en grandes enantioselectividades y en el mejor de los casos se han conseguido los productos en su forma enantioméricamente pura (> 99% ee).
The growing interest in obtaining enantiomerically pure compounds in obtaining enantiomerically pure compounds has led to a significant development in the field of asymmetric catalysis. In this context, this thesis is focused on the synthesis of several families of highly modular chiral ligands from readily available compounds. Specifically, we worked on the synthesis of thioether-phosphite ligands, phosphite-pyridine, phosphite-triazole and hidroaximide and thioamide ligands. They all have in common that are solid, stable and therefore easy to handle. These ligands have been applied in the Rh- and Ir-catalyzed hydrogenation of functionalized and unfunctionalized olefins, in the Ru- and Rh-catalyzed asymmetric transfer hydrogenation of ketones, in Pd-catalyzed allylic substitution reactions and in the Ni-catalyzed addition of organoalumininum to aldehydes. Moreover, in some cases DFT studies have been performed to speed up the optimization of ligands. Hence, a variety of chiral chemical compounds of high synthetic interest (i. e. alcohols, functionalized and non-functionalized alkanes, substituted allyl) lhigh enantioselectivities were achieved and in some cases the products were obtained in their enantiomerically pure form(> 99% ee).
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Vabre, Roxane. "Fonctionnalisation directe de liaisons C-H et couplages croisés pour la formation de liaisons C-C et C-N : synthèse de purines 6,8,9-trisubstituées." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00923198.
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La grande variété de propriétés biologiques associées au noyau purine en fait une structure privilégiée pour la conception et la synthèse de nouvelles molécules à visée thérapeutique. Cette spécificité est étroitement liée à la grande diversité de substituants pouvant être introduits sur les différentes positions du noyau purine et en particulier sur C2, C6, C8 et N9. Par conséquent, le développement de méthodes de fonctionnalisation rapides de cette famille de composés est d'un grand intérêt synthétique. Nous nous sommes focalisés sur la formation de liaisons C-C et C-N sur les positions 6 et 8 du noyau purine pour pouvoir présenter de nouveaux outils de synthèse permettant d'introduire une plus grande diversité fonctionnelle. D'une part, nous avons étudié la fonctionnalisation directe de liaisons C-H de purines, sujet encore peu exploré. En effet, de nos jours, le traditionnel couplage croisé (Negishi, Suzuki-Miyaura), utilisé pour la création de liaisons C-C, se voit de plus en plus concurrencé par ces réactions puisqu'elles ne nécessitent pas la préparation d'un partenaire organométallique. Ce sont des réactions dites à économie d'atomes. En nous basant sur l'expérience du laboratoire dans le domaine de la fonctionnalisation directe de liaisons C-H, nous avons envisagé l'alcénylation et l'alcynylation directes en position 8 de la purine, les motifs alcényle et alcynyle étant présents dans certaines purines d'intérêt biologique. D'autre part, nous nous sommes intéressés à deux méthodes de couplage croisé pallado-catalysé permettant la formation de liaisons C-N et C-C : le couplage de Buchwald - Hartwig entre une 8-iodopurine et des amides ou des amines aromatiques, et le couplage de Liebeskind - Srogl entre une 6-thioétherpurine et divers acides boroniques.
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Sun, Ho-Yan. "Studies on the Mechanism of Direct Arylation of Pyridine N oxides: Evidence for the Essential Involvement of Acetate from the Pd(OAc)2 Pre-Catalyst at the C-H Bond Cleaving Step." Thesis, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19760.
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Detailed mechanistic studies on the palladium-catalyzed direct arylation of pyridine N-oxides are presented. The order of each reaction component is determined to provide a general mechanistic picture. The C-H bond cleaving step is examined in further detail through computational studies, and the calculated results are in support of an inner-sphere concerted metallation-deprotonation (CMD) pathway. Competition experiments were conducted using N-oxides of varying electronic characters, and results revealed an enhancement of rate when using a more electron-deficient species which is in support of a CMD transition state. The effect of base on reaction rate was also examined and it was found that a carboxylate base was required for the reaction to proceed. This led to the conclusion that Pd(OAc)2 plays a pivotal role in the reaction mechanism as more than merely a pre-catalyst, but as a source of acetate base required for the C-H bond cleavage step.
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Guyonnet, Mathieu. "Synthèse totale d’alcaloïdes de type dibenzopyrrocoline par arylation C(sp3)-H intramoléculaire." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10143.
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La fonctionnalisation de liaisons carbone – hydrogène réputées peu réactives ouvre de nouvelles perspectives en synthèse organique. Une stratégie efficace consiste en l'utilisation de métaux de transition comme le palladium. L'activation C-H organométallique a fait l'objet de nombreux développements méthodologiques au cours des dernières décennies, toutefois peu d'applications de ces travaux en synthèse multi-étapes ou totale sont reportées dans la littérature. Les travaux de recherche décrits dans ce mémoire s'inscrivent dans ce contexte. Nous nous sommes intéressés à la famille des alcaloïdes de type dibenzopyrrocoline, une famille de produits naturels structurellement originaux. Au vu des travaux précédemment reportés dans la littérature, l'analyse rétrosynthétique de ces produits nous a conduits à développer dans un premier temps une séquence N-arylation / bromation / arylation C(sp3)-H intramoléculaire de lactames et analogues qui nous a permis d'accéder à diverses indolines tricycliques fusionnées. Dans un deuxième temps, la synthèse du squelette dibenzopyrrocoline a été entreprise à l'aide de la méthodologie séquentielle développée et la difficulté d'accès au précurseur d'arylation C(sp3)-H intramoléculaire a nécessité l'exploration de différentes voies synthétiques, potentiellement prometteuses. Enfin les différents travaux méthodologiques effectués ont mis à jour la faisabilité de l'arylation C(sp3)-H intramoléculaire d'anilines tertiaires, jamais reportée dans la littératureThe direct functionalization of unactivated C-H bonds represents an atom- and stepeconomical alternative to more traditional synthetic methods based on functional group interconversion. Transition-metal catalysis has recently emerged as a powerful tool to functionalize otherwise unreactive C-H bonds. Whereas a lot of methodological studies have been developed in the past decade, few applications of these methodologies in multi-step or total synthesis have been reported in the literature. In this context, we envisioned the total synthesis of dibenzopyrrocoline alkaloids, a family of structurally original natural products, by using intramolecular C(sp3)-H arylation as a key step. This work led us to first develop a N-arylation / bromination / intramolecular C(sp3)-H arylation sequence which allowed us to access diverse fused tricyclic indolines. We next investigated the application of this strategy to the synthesis of the dibenzopyrrocoline motif. The difficulty to access the C(sp3)-H arylation precursor required an exploration of different synthetic pathways, which proved to be potentially promising. Finally the different performed methodological studies showed the feasibility of the intramolecular C(sp3)-H arylation of tertiary anilines, which was never described in the literature
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Haslinger, Stefan [Verfasser], Fritz Elmar [Akademischer Betreuer] Kühn, Ulrich K. [Akademischer Betreuer] Heiz, Richard W. [Akademischer Betreuer] Fischer, and Jean-Marie [Akademischer Betreuer] Basset. "Bioinspired Iron N-Heterocyclic Carbene Complexes in C–H Bond Oxidation: Reactivity, Electronic Properties, and Catalytic Activity / Stefan Haslinger. Betreuer: Fritz Elmar Kühn. Gutachter: Ulrich K. Heiz ; Richard W. Fischer ; Fritz Elmar Kühn ; Jean-Marie Basset." München : Universitätsbibliothek der TU München, 2015. http://d-nb.info/1080299270/34.
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Filipczyk, Grzegorz Paweł. "Ferrocenyl-Alkynes and Butadiynes: Reaction Behavior towards Cobalt and Iron Carbonyl Compounds." Doctoral thesis, Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-231913.
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Die vorliegende Dissertation beschreibt die Synthese und Charakterisierung von neuartigen perferrocenylierten, cyclischen Komplexen unter Anwendung der Cobalt-vermittelten Cyclomerisierung in Kombination mit einer C-H-Bindungsaktivierung als auch die Bildung von ferrocenylierten Phosphinoalkinid-Komplexen mit Eisen- und Cobaltcarbonylen. Die elektrochemischen Eigenschaften und die Elektronentransfer-prozesse zwischen den terminalen Ferrocenyleinheiten in den unterschiedlichen cyclischen Verbindungen wurden unter Einbeziehung der Struktur/chemischen Zusammensetzung der Brückenbausteine ermittelt. Elf perferrocenylierte, cyclische Komplexe wurden mittels [2+2] bzw. [2+2+2] Cyclomerisierung von 1,4-Diferrocenylbutadiin FcC≡C–C≡CFc (Fc = Fe(η5-C5H4)(η5-C5H5)) unter Verwendung von Dicarbonylcyclopentadienylcobalt Co(η5-C5H5)(CO)2 erhalten. Diese können in drei Gruppen unterteilt werden: (i) Produkte der Cyclodimerisierung mit zusätzlicher Kettenverlängerung, welche Cyclobutadienyl-einheiten als zentrale Brückenbausteine besitzen (3a,b und 4a,b), (ii) Produkte der Cyclodimerisierung mit gleichzeitiger CO-Insertion (6a,b,c und 7), und (iii) Produkte der Cyclotrimerisierung gefolgt von einem Ringschluss durch eine C-H-Bindungsaktivierung (5a,b,c). Die Optimierung der Reaktionsbedingungen wurde zur Ausbeutemaximierung der jeweiligen Verbindungsfamilien durchgeführt. Ein weiterer Teil dieser Forschungsarbeit bezieht sich auf die verschiedenen Reaktionsmuster von (Ferrocenylethinyl)diphenylphosphan- mit zweikernigen Eisen- bzw. Cobaltcarbonylverbindungen in Form von Dieisennonacarbonyl und Dicobaltoctacarbonyl als Reagenzien. Dabei konnten sechs gemischte Carbonyl- und Ferrocenyl-funktionalisierte Phosphinoacetylid-Komplexe mit Eisen(0) und Cobalt(0) erhalten und charakterisiert werdenThe present PhD study focuses on the synthesis and characterization of novel perferrocenylated cyclic complexes utilizing cobalt - mediated cyclomerization in combination with C–H bond activation as well as formation of ferrocenylated phosphino-alkyne compounds with iron and cobalt carbonyls. Electrochemical properties and electron-transfer processes between terminal ferrocenyl units in the diverse cyclic compounds are explored in relation to the chemical composition of the building blocks connecting them. Eleven perferrocenylated cyclic compounds were obtained via [2 + 2] and [2 + 2 + 2] cyclomerization of 1,4-diferrocenylbutadiyne FcC≡C–C≡CFc (Fc = Fe(η5-C5H4)(η5-C5H5)) by the reaction with dicarbonylcyclopentadienylcobalt Co(η5-C5H5)(CO)2. They are subdivided into three groups: (i) products of cyclodimerization with additional chain extension, possessing cyclobutadienyl moieties as a central linkage unit (3a,b and 4a,b), (ii) products of cyclodimerization with consecutive CO insertion (6a,b,c and 7), and (iii) products of cyclotrimerization followed by cycle formation via C–H bond activation (5a,b,c). Optimization of the reaction conditions was made in order to maximize the amount of each group of compounds. Furthermore, another part of this research work focuses on diverse reaction patterns of (ferrocenylethynyl)diphenylphosphane with diironnonacarbonyl and dicobaltocta-carbonyl. Six mixed carbonyl and ferrocenyl-functionalized phospinoalkynyl compounds of iron(0) and cobalt(0) were obtained and characterized
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Toure, Momar Gaya. "Petites variations autour de la chimie de l'imidazole et du bore : de la catalyse aux récepteurs d'anions." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4365.
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La conception et l’élaboration de nouveaux ligands en chimie organométallique évoluent vers le design de ligands multifonctionnels afin d’augmenter l'affinité ligand/métal/substrat et de mimer les catalyseurs de la nature comme les enzymes, en activant de manière synergique les différents partenaires de la réaction. Il existe dans la littérature très peu d’exemples de complexes organométalliques présentant une fonctionnalité acide de Lewis. Dans notre étude, nous avons opté pour l’utilisation d’un atome de bore trivalent pendant. Malgré la forte utilisation des dérivés du bore en catalyse acide de Lewis pour l’activation de divers électrophiles, la conception de tels ligands ambiphiles, pour des complexes organométalliques, a été peu décrite et la réactivité peu étudiée. Ce travail a donc pour but d’explorer et de valider la viabilité de leurs préparations et de leurs utilisations.La première partie de ces travaux a été consacrée au développement de nouveaux complexes bifonctionnels métal/NHC/ester boronique pendant de Pd(II), Rh(I), Ru(II), Au(I) et Cu(I) et leurs applications en catalyse, afin d’accéder à de nouveaux modes d’activation de petites molécules.Dans la deuxième partie, un nouveau mode d’activation efficace de la liaison B-H des carbènes boranes incorporant un bras allylique ou homoallylique par des complexes de rhodium pour accéder à une famille de NHC-boranes cycliques énantioenrichis a été développé.Enfin, la troisième partie constitue la synthèse des travaux sur deux nouvelles familles de cations boronium macrocycliques et leurs applications dans la reconnaissance des anionsConception and elaboration of new ligands in organometallic chemistry evolved towards the design of multi-functional shape to increase the affinity ligand/metal/substrate to mimic nature’s catalysts, and to promote, in most cases, an increasing reactivity and selectivity in the catalytic process. Despite the significant development of N-heterocyclic carbene (NHC) ligands in organometallic chemistry since the last decade, complexes bearing pendant trivalent boron derivatives were so far overlooked.In this context, bifunctional ligands containing NHC and boron moieties have been developed and the corresponding Ag(I), Pd(II), Rh(I), Cu(I) and Ru(II) complexes were designed and prepared for a synergistic activation of both reaction partners by the metal center and the pendant Lewis acidic boron atom.During this work, B−H bond activation of NHC-boranes by a diphosphane-ligated cationic Rh complex was applied in an unprecedented intramolecular enantioselective hydroboration of simple olefins. This study led to a library of enantioenriched cyclic boranes in high yields (up to 94%) with high regio- (up to 100%) and enantioselectivities (er up to 99.2:0.8).As part of this work, new boronium macrocycles were synthesized in high yields and their anion binding ability was evaluated by fluorimetric and 1H NMR titration. These new macrocycles display high binding affinity for halides and oxoanions in the solid state, in solution and in the gas phase
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Börger, Carsten, Olga Kataeva, and Hans-Joachim Knölker. "Novel approach to biscarbazole alkaloids via Ullmann coupling – synthesis of murrastifoline-A and bismurrayafoline-A." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-139195.
Full textAbstract:
Unprecedented Ullmann couplings of murrayafoline-A with either 6-bromo- or 4-bromocarbazole derivatives provide highly efficient synthetic routes to the biscarbazole alkaloids murrastifoline-A (6 steps, 66% overall yield) and bismurrayafoline-A (6 steps, 28% overall yield)Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Börger, Carsten, Olga Kataeva, and Hans-Joachim Knölker. "Novel approach to biscarbazole alkaloids via Ullmann coupling – synthesis of murrastifoline-A and bismurrayafoline-A." Royal Society of Chemistry, 2012. https://tud.qucosa.de/id/qucosa%3A27811.
Full textAbstract:
Unprecedented Ullmann couplings of murrayafoline-A with either 6-bromo- or 4-bromocarbazole derivatives provide highly efficient synthetic routes to the biscarbazole alkaloids murrastifoline-A (6 steps, 66% overall yield) and bismurrayafoline-A (6 steps, 28% overall yield).Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Morgan, Erin. "Rhodium and Iridium Pincer Complexes Supported by Bis(phosphino)silyl Ligation: Applications in Bond Cleavage Chemistry." 2013. http://hdl.handle.net/10222/27968.
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Group 9 transition metal pincer complexes have shown tremendous utility in a variety of E-H (E = main group element) bond activation reactions. In an effort to access new types of highly reactive pincer-like transition metal complexes this research focuses on the development of new late metal complexes supported by tridentate bis(phosphino)silyl ligands of the type [?3-(2-R2PC6H4)2SiMe]- ([R-PSiP]; R = Cy, iPr). The incorporation of a strongly electron donating and highly trans-labilizing silyl group at the central anionic position may promote the formation of new coordinatively unsaturated compounds capable of enhanced reactivity. In this regard, the synthesis of coordinatively unsaturated Rh and Ir complexes supported by R-PSiP ligation and their ability to activate E-H bonds will be detailed.
The synthesis of Cy-PSiP ligated Rh and Ir species and the ability to access the products of N–H bond oxidative addition with these species was investigated. Both [Cy-PSiP]Rh and [Cy-PSiP]Ir complexes were shown to form isolable complexes of the type [Cy-PSiP]M(H)(NHR) (M = Rh, R = aryl; M = Ir, R = H, aryl). However, attempts to generate such amido hydride complexes by N-H activation of the corresponding amine led to divergent reactivity, where adducts of the type [Cy-PSiP]Rh(NH2R) were obtained for Rh, while N-H bond oxidative addition was observed for Ir to form the targeted amido hydride complexes, including a rare example of ammonia N-H bond oxidative addition to form a monomeric, terminal parent amido complex that was crystallographically characterized. Due to the scarcity of transition metal complexes that are capable of N-H bond oxidative addition, a thorough investigation of the N-H bond activation mediated by [Cy-PSiP]Rh and Ir with various N-H containing substrates, including alkyl amines, hydrazine derivatives, and benzamides was initiated. Extension of this reactivity to the related diisopropylphosphino derivative [iPr-PSiP]IrI was also probed, as the resulting complexes were envisioned to be less susceptible to potential cyclometalation processes.
Indeed, oxidative addition of primary alkyl amines, hydrazines, and benzamides was observed for [R-PSiP]Ir. These results comprise an unprecedented example of a metal complex that is capable of facile N-H bond activation in such a wide range of substrates, including challenging substrates such as ammonia and alkyl amines. A rare example of Rh-mediated N-H oxidative addition was also observed for the reaction of [Cy-PSiP]RhI with benzophenone hydrazone.
The potential for these [R-PSiP]Ir(H)(NHR) complexes to insert unsaturated substrates was investigated, as the development of new pathways for the formation of C-N bonds via transition metal catalyzed N-H bond oxidative addition to a metal center followed by insertion of an alkene or alkyne into the M-N or M-H bond may provide a new pathway for accessing intermolecular amination reactions. Insertion chemistry attempts with various alkenes, alkynes, allenes, C=O and C?N containing compounds is described.
Lastly, the synthesis of IrIII complexes of the type {[R-PSiP]IrR'}+X? (R = Cy, iPr; R’ = H, Me; X = OTf, BF4, B(C6F5)4) and their interactions with the C-H bonds of arenes and aldehydes, as well as, the Si-H bonds of hydrosilanes is detailed. The Si-H bond activation chemistry observed was typically influenced by the counter anion X. Thus, the more coordinating anions OTF and BF4 were shown to coordinate to and stabilize the highly electrophilic Si in transiently generated Ir silylene species.
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Lin, Yan-Duo, and 林彥多. "Intramolecular Electron Transfer Induced C-N Bond Cleavage and Exciplex Formation of the double bond Constrained Aminostilbenes Derivatives." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/30731139014850662384.
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博士國立中央大學
化學研究所
96
This thesis is aimed to study the relationship between the photoinduced intramolecular electron transfer processes and the excited-state C-N bond cleavage reaction as well as intramolecular exciplex formation of a series of amine-bridge-stilbene derivatives. The fluorescence spectra of DPhI, MPhI and DEtI show dual fluorescence in polar solvents, but DCEtI and DPyI display only the locally-excited (LE) fluorescence in both nonpolar and polar solvents. Compounds DPhI and MPhI in nonpolar and polar solvents and DPyI and DPyCI in CH3CN undergo the C-N bond cleavage, leading to the formation of HI and CI of higher fluorescence quantum yields (Φf). However, such a C-N bond fragmentation reaction was not observed for DEtI in either nonpolar or polar solvents. The Φf and the quantum yields of the C-N bond cleavage reaction (Φfra) for DPyI and DPyCI increase as increasing the solvent polarity. In contrast, an opposite solvent dependence of Φfra was observed for DPhI and MPhI because the intramolecular electron transfer and back electron transfer processes locate in the Marcus normal and inverted region, respectively, and the value of ΦBET increases more than that of ΦICT with increasing the solvent polarity. Compounds DPyI2 and DPyI3 display only the LE fluorescence in both nonpolar and polar solvents, but the fluorescence quantum yields decrease and the fluorescence life times increase with increasing the solvent polarity. This indicates the presence of electron donor and acceptor interactions. Compounds DPhI2 and DPhI3 show dual fluorescence in moderate and highly polar solvents, and the long-wavelength emission band results from intramolecular exciplexes. When compared with the one-mothylene-bridged compounds, compounds DPyI2, DPyI3, DPhI2 and DPhI3 do not undergo the cleavage of C-N bond in both nonpolar and polar solvents.
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黃邦齊. "Copper-Catalyzed Oxidative C–H Functionalization and C–N Bond Formation Reactions." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/20012303017376429959.
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博士國立清華大學
化學系
101
Synthesis of biologically active heterocyclic compounds via transition-metal-catalyzed direct transformation of an inactivated C–H bond into C–N bond is an emerging field in organic synthesis. Mostly these metal-catalyzed reactions are significantly introducing simple conversions and reduce reaction steps and cost. With this regards, this thesis described four new reactions for C–H bond functionalization and C–N bond formation via copper-catalyzed oxidative coupling reaction. In first chapter, we choose CuI and 2,2'-bipyridine to generate Cu(II)OH complex which can successfully proceeding sp2 C–H bond activation and intramolecular cyclization reactions to give acridone products by radical pathway. This reaction can be easily extended to various intermolecular cyclization, total synthesis of N-Methyl Toddaliopsin A and Arborinine with excellent yield. The 2nd chapter focuses on copper-catalyzed intermolecular oxidative C–N coupling reaction of acetophenone with amine hydrochloride salt. The catalytic system proceeds via superoxide radical subsequent acetophenone oxidation to give aryl glyoxal, and then last one react with amine to produce α-ketoamide. Chapter 3 deals with the combination of chapter 1 and 2. The reaction of Cu(II)OH complex with 2'-aminoacetophenone to give isatin via intramolecular direct oxidative C–H amination. This simple method offers an alternative, cheap path way to form isatin through C–N and C–O bond formation. The final chapter describes the copper-catalyzed oxidative amidation of alcohols with amine hydrochloride salts. This reaction condition provides an occasion for the synthesis of different aryl amides by less expensive catalyst.
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Giunta, Daniela [Verfasser]. "New approaches to catalytic C-H and C-C bond cleavage with ruthenium complexes / vorgelegt von Daniela Giunta." 2004. http://d-nb.info/972586830/34.
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Brozell, Alec John. "[Alpha]-amination of ketones and protected ketones using dialkyl azodicarboxylates as a nitrogen source." Thesis, 2011. http://hdl.handle.net/2152/23480.
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[Alpha]-Amino ketones can serve as important intermediates for the synthesis of biologically active molecules, and making these precursors in a practical manner has long been a challenge for organic chemists. The oxygen-carbon-carbon-nitrogen (O-C-C-N) sequence is common in natural and synthetic compounds of biological interest, due in part to their relatedness to peptides. Because of the many known carbonyl transformations, [alpha]-amino ketones have the potential to form various amine derivatives. Herein we present our research endeavors which led to several novel methods of forming this type of functionality. These endeavors culminated with the development of a two-step hydrazidation/N-N bond cleavage technique for forming [alpha]-amino ketals--which can be readily hydrolyzed to [alpha]-amino ketones.text
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Barfüßer, Sebastian Ulrich. "Kupfer- und palladiumkatalysierte N H- und C H-Bindungsfunktionalisierungen zur effizienten Synthese von Heterocyclen." Doctoral thesis, 2011. http://hdl.handle.net/11858/00-1735-0000-0006-B09A-0.
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Hsu, Kao-Chi, and 許高旗. "Palladium-catalyzed mono- and di-alkenylation of N-acetyl-2-aminobiaryls via regioselective C-H bond activation." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/97414932070771308222.
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Xiang, Shengqi. "Structural insights into Arginine-Serine rich proteins and N-H spin-spin coupling constants." Doctoral thesis, 2013. http://hdl.handle.net/11858/00-1735-0000-0001-BB00-1.
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Huang, Hao-ping, and 黃皓平. "Palladium(II)-Catalyzed Direct Ortho Arylation of 4-Methyl-N-phenylpyridin-2-amines via Suzuki-Miyaura Type C-H Bond Activation/C-C Bond Coupling." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/33597258074376514286.
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碩士國立中山大學
化學系研究所
101
The direct ortho arylation of 4-methyl-N-phenylpyridin-2-amines via palladium(II)-catalyzed C-H activation is described. Treatment of 4-methyl-N-phenylpyridin-2-amine with potassium aryltrifluoroborate using ten mol % of Pd(OAc)2 as the catalyst, two equivalents of copper (II) acetate as the oxidant and one equivalent of p-benzoquinone in tert-butyl alcohol gave the ortho-arylated products in modest to excellent yields. This reaction shows good functional group compatibility. A series of controlled experiments and 1H NMR titration experiments for the reaction were carried out. The key intermediate, 4-methyl-N-phenylpyridin-2-amine palladacycle was isolated and characterized by X-ray crystallography. A rational mechanism for the catalytic reaction is presented. The advanced transformations of ortho phenylated 4-methyl-N-phenylpyridin-2-amine to N-(4-methylpyridine-2-yl)-9H-carbazole, biphenyl-2-amine, and 3-methyl-6-phenylpyrido[1,2-a]-benzimidazole were successfully demonstrated.
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Wu, Yi-Wen, and 吳翌彣. "The Study of Electronic Structures of Five-coordinate Saddled Iron(III) Porphyrin Radical Cation and O-O Bond Homolytic Cleavage of (OETPP)FeIIIO(H)OtBu." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/n6af3q.
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碩士國立中興大學
化學系所
106
In this study, paramagnetic NMR spectroscopy, X-ray diffraction, magnetic susceptibility and DFT calculation are employed to elucidate the strong bonding interaction between iron(III) dx2-y2 and porphyrin a2u orbitals of [Fe(OMTPP∙)Cl]SbCl6 and [Fe(OETPP∙)Cl]SbCl6. Their crystal structures clearly indicate that their saddle deformations are increased compared to those prior to oxidations. Their 1H NMR data present the S = 2 states for such one-electron oxidation states, and demonstrate that their structures in solutions remain strong saddle deformations. In light of 1H NMR spectroscopy of [Fe(TPP∙)Cl]SbCl6 resembling to the above cases, we postulate that the ring structure of [Fe(TPP∙)Cl]+ may possess strongly saddle to have great bonding interaction between iron(III) dx2-y2 and porphyrin a2u orbitals. In the DFT calculations, the degrees of phenyl ring rotation and saddled deformation will also affect their NMR spectra. In another topic, we observe O-O bond homolytic cleavage of (OETPP)FeIIIO(H)OtBu formed in the reaction of Fe(OETPP)ClO4 with TBHP and its activation parameters (ΔH≠ = 47(2) kJ mol-1, ΔS≠ = 83(9)J mol-1K-1) is measured by low-temperature UV-vis spectral data. The corresponding one-electron oxidation product is identified as [Fe(OETPP∙)OH]+, which is an isoelectronic structure as oxoiron(IV) porphyrin, by UV-vis, NMR spectroscopy and ESI-MS spectrometry. According to the experiments of NMR and ESI-MS, we also find that ·OtBu radical will convert Fe(OETPP)ClO4 to [Fe(OETPP∙)OtBu]+. Furthermore, these related iron(III) porphyrin radical cations can be carried out one more electron oxidation to isoporphyrins, an isoelectronic structure as Compound I. These iron(III) saddled isoporphyrins are shown to be reactive for highly selective chlorination of cyclohexene.
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Mahoney, Stuart James. "Innovative Methods for the Catalyzed Construction of Carbon-Carbon and Carbon-Hydrogen Bonds." Thesis, 2012. http://hdl.handle.net/10012/7015.
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The selective transformation of carbon-carbon and carbon-hydrogen bonds represents an attractive approach and rapidly developing frontier in synthesis. Benefits include step and atom economy, as well as the ubiquitous presence in organic molecules. Advances to this exciting realm of synthesis are described in this thesis with an emphasis on the development of catalytic, selective reactions under mild conditions. Additionally some applications of the methodologies are demonstrated.
In Chapter 1, the first examples of inter-and intramolecular enantioselective conjugate alkenylations employing organostannanes are reported. A chiral, cationic Rh(I)-diene complex catalyzed the enantioselective conjugate addition of alkenylstannanes to benzylidene Meldrum’s acids in moderate enantiomeric ratios and yields. Notably, the cationic and anhydrous conditions required for the asymmetric alkenylation are complementary to existing protocols employing other alkenylmetals.
In Chapter 2, a domino, one-pot formation of tetracyclic ketones from benzylidene Meldrum’s acids using Sc(OTf)3 via a [1,5]-hydride shift/cyclization/Friedel-Crafts acylation sequence is described. Respectable yields were obtained in accord with the ability to convert to the spiro-intermediate, and considering the formation of three new bonds: one C-H and two C-C bonds. An intriguing carbon-carbon bond cleavage was also serendipitously discovered as part of a competing reaction pathway.
In Chapter 3, the pursuit of novel C-H bond transformations led to the development of non-carbonyl-stabilized rhodium carbenoid Csp3-H insertions. This methodology enabled the rapid synthesis of N-fused indolines and related complex heterocycles from N-aziridinylimines. By using a rhodium carboxamidate catalyst, competing processes were minimized and C-H insertions were found to proceed in moderate to high yields. Also disclosed is an expedient total synthesis of (±)-cryptaustoline, a dibenzopyrrocoline alkaloid, which highlights the methodology.
In Chapter 4, the Lewis acid promoted substitution of Meldrum’s acid discovered during the course of the domino reaction was explored in detail. The protocol transforms unstrained quaternary and tertiary benzylic Csp3-Csp3 bonds into Csp3-X bonds (X = C, N, H) and has even shown to be advantageous with regards to synthetic utility over the use of alternative leaving groups for substitutions at quaternary benzylic centers. This reaction has a broad scope both in terms of suitable substrates and nucleophiles with good to excellent yields obtained (typically >90%).
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Hsiao, Huan-Chang, and 蕭煥璋. "Palladium-catalyzed dual fold C-H bond activation of N-acetyl-2-aminobiaryl with in situ diyne in one pot." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/4s52ap.
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Huang, Wen-Lin, and 黃玟琳. "Ruthenium-Mediated C－N and C－C Bond Formation between Terminal Acetylenes and Amines: Hydroamination/C－H Activation, Double Hydroamination and Metathesis Products." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/66241500888130743811.
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碩士臺北市立教育大學
應用物理暨化學系化學組碩士班
100
Reaction of the benzophenone imine complex (NH=CPh2)[Ru]-Cl (2) {[Ru] = Tp(PPh3)Ru; Tp = HB(pz)3, pz = pyrazolyl} with terminal alkyne HCºCR afforded the alkenyl ketone complex (R = CH2Ph (4)) and the η3-allylic complex (R = p-C6H4(CF3) (5) , m-CH3C6H4 (6)), respectively. Intriguingly, one-pot reaction of 2 with phenylacetylene HCºCPh and methylamine in refluxing methanol, through C-H bond activation of N-methylamine and N-C bond formation of the vinylidene ligands, resulted in the formation of aminocarbene (12)、(13), azetidinylidene (7)~(11) and metalladihydropyridine (14) complexes, where the product distribution depended on the reaction conditions. Significantly, protonation of 11 in CH2Cl2 affored the ruthenium ketenimine complex (17), organic alkyne (p-OCH3C6H4)CºCH and alkene (p-OCH3C6H4)HC=CH2. Preliminary results on the protonation of 14 are also presented. The structures of 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15 and 17 have been determined by X-ray diffraction analysis.
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Hsieh, Tom Han-Hsiao. "Transition Metal Catalysis: Construction of C–N and C–C bonds en route to Nitrogen Heterocycles, Chiral Esters and 6-deoxyerythronolide B." Thesis, 2011. http://hdl.handle.net/1807/31784.
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The Dong research group is interested in harnessing the power of transition metal catalysis to transform simple molecules and reagents (such as carbon monoxide, hydrogen gas, olefins, and C–H and C–O bonds) into valuable products (such as functionalized heterocycles, chiral carbonyl compounds and natural products). This thesis will describe our continual effort to achieve this goal.
Part I describes the Pd-catalyzed functionalization of sp2 and sp3 C–H bonds. Carbon monoxide is used as a stoichiometric reductant in the cyclization of diarylnitroalkenes to afford biologically relevant 3-arylindoles and other N-containing heterocycles with carbon dioxide as the only stoichiometric byproduct. Also, an aryl sulfoxide moiety is shown to direct the arylation of sp3 C–H bonds to afford beta-functionalized amides.
Part II describes the Ru-catalyzed sp3 C–O bond activation of alkoxypyridines and related heterocycles. In this transformation, an O- to N-alkyl migratory rearrangement occurs to afford N-alkylated pyridones which are structures found in many natural products and pharmaceutical agents.
Part III describes our pursuit of metal-catalyzed asymmetric synthesis. Readily available benzylic bromides are carbonylated with carbon monoxide in alcoholic solvent mixtures. The resulting medicinally relevant 2-arylpropionic esters are obtained with moderate to good enantioselectivities. Preliminary results for the asymmetric hydrogenation of gem-diarylethylenes and novel ligand development are also disclosed.
Part IV describes our efforts towards the total synthesis of 6-deoxyerythronolide B. Our retrosynthetic analysis of the macrolide antibiotic involves disconnections at the lactone linkage and between C7 and C8. The two equally complex fragments were prepared via reliable aldol, hydroboration, crotylation and redox chemistry. Rather than the typical macrolactonization method to form the 14-membered ring, we propose an alternative strategy where we plan to cyclize with a metal-catalyzed ring-closing metathesis event. Currently, this step is under investigation by other members in the group.
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Tung, Tsu-Chien, and 童子謙. "Synthesis of Poly(3-hexylthiophene), Poly(3-hexylselenophene) and Poly(3-hexylthiophene-alt-3-hexylselenophene) by Direct C-H Bond Arylation via N-Heterocyclic Carbene Palladium Catalysts." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/4w89ub.
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碩士國立交通大學
應用化學系碩博士班
102
In this study, we have successfully introduced commercial N-heterocyclic carbene-based palladium catalysts to conduct direct C-H bond arylation polymerization and poly(3-hexylthiohphene) (P3HT), poly(3-hexylselenophene) (P3HS), and poly(3-hexylthiophene-alt-3-hexylselenophene) (P3HTS) were synthesized accordingly. Under our optimized conditions, high molecular weight P3HT (Mn = 26.9 k, PDI = 3.56) with high head-to-tail regioregularity (94%) was prepared through C-H bond arylation polymerization catalyzed by NHC-Pd(II) [1,3-Bis(2,6-diisopropylphenyl)imidazol-2-ylidene]chloro[3-phenylallyl]palladium(II). P3HS was obtained by a similar manner and this is the first example of preparing P3HS by direct C−H bond arylation. NHC-Pd(II) exhibits a wide range of working temperature spanning from 70°C to 140°C) and good catalytic reproducibility relative to conventional phosphine-based palladium catalysts. For this first time head-to-tail poly(3-hexylthiophene-alt-3-hexylselenophene) was prepared by direct C-H bond arylation polymerization by the help of NHC-Pd(II), offering an opportunity to study the physical properties of P3HTSThe results reveal that P3HTS retains many advantageous properties of P3HT and P3HS, including broad UV-Vis absorption, good crystallinity, and high thermal stability (Td = 428 °C). Moreover, owing to the regular alternating arrangement of thiophene and selenophene units, it also exhibits various advantages over either P3HT or P3HS, such as more red-shifted absorption maximum (462 nm) than P3HT, narrower electrochemical HOMO−LUMO gap (2.21 eV) and better solubility relative to P3HS. In brief, our results provide an economical and convenient method for the direct C−H bond arylation polymerization of thiophene-selenophene alternating copolymer. It is envisaged that the employed methodology in this study can be further applied to synthesis of other alternating copolymers such as thiophene-tellurophene andselenophene-tellurophene alternating copolymers.
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Gallo, Elizabeth A. "Conformation-directing effects of intramolecular hydrogen bond formation Part I: N-H--(pi) hydrogen bonding in a norbornenyl diamide : Part II: -̉helical turn formation in small model depsipeptides /." 1993. http://catalog.hathitrust.org/api/volumes/oclc/30840836.html.
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Bartholoméüs, Johan. "Réactions d’amination de liens C-H : synthèse d’amines propargyliques à partir de N-mésyloxycarbamates et études mécanistiques." Thèse, 2016. http://hdl.handle.net/1866/18430.
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Les composés aminés représentent une grande part des substances actives en chimie médicinale. Les travaux rapportés dans cette thèse décrivent les efforts consacrés au développement d’une nouvelle méthode d’amination de liens C-H propargyliques. Notre groupe de recherche a développé depuis quelques années un nouveau précurseur de nitrène métallique, les N-mésyloxycarbamates, permettant d’effectuer des réactions d’amination de liaisons C-H diversement activées. Au cours du développement de notre méthodologie, la synthèse du N-mésyloxycarbamate a fait l’objet de nombreuses optimisations, notamment en améliorant l’échelle globale de la synthèse ainsi que son efficacité. De même, des efforts ont été consacrés pour diminuer le nombre d’étapes nécessaires à la synthèse du réactif en développant la synthèse d’un des intermédiaires de manière énantiosélective. Enfin, la synthèse de ce réactif a également été envisagée à l’aide de la chimie en flux continu.
Au cours du développement de la méthode de synthèse d’amines propargyliques, nous avons constaté que l’acide acétique jouait un rôle déterminant dans la conservation de bonnes sélectivités et réactivités de la réaction. Ces différentes observations ont permis de mettre au point un procédé diastéréosélectif efficace permettant d’obtenir des amines propargyliques avec des rendements allant de moyens à bons et avec d’excellentes diastéréosélectivités.
A la suite de l’étude de l’étendue de notre procédé, nous avons tenté de déterminer les mécanismes réactionnels qui régissaient la réactivité et la sélectivité de celui-ci. Nous avons ainsi montré que l’espèce réactive du système catalytique était bel et bien un nitrène métallique, et que l’étape cinétiquement déterminante était celle d’insertion. Des expériences faites en oxydant l’espèce catalytique de rhodium ont suggéré que plusieurs états d’oxydation de cette espèce peuvent être présents et actifs dans le système catalytique.The nitrogen containing compounds represent a large portion of the active substances in medicinal chemistry. The work reported in this manuscript describe the efforts devoted to the development of a new method of amination of propargylic C-H bonds. Our research group has developed recently a new metal nitrene precursor, N-mesyloxycarbamates, to perform amination reactions on various C-H bonds. During the development of our methodology, the synthesis of N-mesyloxycarbamate has undergone many improvements, including improved global scale synthesis and effectiveness. Similarly, efforts were devoted to reduce the number of steps required for the synthesis of the reagent by developing the synthesis of an intermediate enantioselectively. Finally, the synthesis of this reagent was also considered using continuous flow chemistry. During development of the method of synthesis of propargylic amines, we have found that acetic acid plays a key role in the conservation of good selectivity and reactivity of the reaction. These observations allowed to develop an efficient diastereoselective process in order to obtain propargylic amines with moderate to good yields and with excellent diastereoselectivities. Following the study of the scope of our process, we tried to determine the reaction mechanisms governing the reactivity and selectivity. We have shown that the reactive species of the catalyst system was indeed a metal nitrene, and that the rate-determining step was the insertion. Experiments made by oxidizing the rhodium catalytic species suggested that several oxidation states of this species may be present and active in the catalytic system.
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Lee, Tai-Hua, and 李岱樺. "Palladium-catalyzed oxidative insertion of carbon monoxide to N-sulfonyl-2-aminobiaryls and 2-phenylphenols through C−H bond activation: access to bioactive phenanthridinone and benzopyranone derivatives in one pot." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/88753078776312877784.
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碩士國立交通大學
應用化學系碩博士班
101
In this thesis, we investigated palladium-catalyzed oxidative carbonylation of N-sulfonyl-2-aminobiaryls through C–H bond activation and C–C, C–N bond formation under milder conditions to synthesize bioactive phenanthridinone derivatives in one pot, and we also applied the method of palladium-catalyzed oxidative carbonylation to 2-aryphenols via one O–H and C–H bond cleavage and one new C–C and C–O bond formation under similar conditions. Both reactions tolerated a variety of substrates and provided biologically important phenanthridinone and benzopyranone derivatives with moderate to excellent yields. In this study, we also optimized the reaction conditions and discussed the reactivity of different functional groups as starting materials. NMR, IR, MS and X-ray diffraction techniques were used to characterize these carbonylation derivatives.
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ZHAO, YIGANG. "Reduction of Tertiary Benzamides to Benzaldehydes by an in situ-Generated Schwartz Reagent (Cp2Zr(H)Cl); Formal Synthesis of Lysergic Acid 2. Ru-Catalyzed Amide-Directed Aryl C-H, C-N and C-O Bond Functionalizations: C-B Formation, C-C Suzuki Cross Coupling and Hydrodemethoxylation." Thesis, 2010. http://hdl.handle.net/1974/6671.
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Chapter 2 of the thesis describes a highly efficient in situ method for the reduction of amides to aldehydes and aryl O-carbamates to phenols and other transformations involving hydrozirconations. The method, as a three-component-type reaction, involves in situ generation of the Schwartz reagent (Cp2Zr(H)Cl) from Cp2ZrCl2 and the reductant, LiAlH(O-t-Bu)3, and immediate reaction with a substrate. Substrates include aliphatic and aromatic tertiary amides which are reduced to aldehydes, aryl O-carbamates which are reduced to phenols, and alkynes which undergo other transformations via hydrozirconation. Compared to prior methods, this method has advantage in that reagents are inexpensive and stable, reaction times are short, and reaction temperatures are generally conveniently at room temperature. The use of the in situ method described herein instead of the requirement for the synthesis of the commercially available Schwartz reagent is estimated to provide more than 50% reduction in cost.
Chapter 3 of the thesis describes the discovery and development of efficient and regioselective Ru-catalyzed amide-directed C-H, C-N, C-O activation/C-C bond forming reactions, ester-directed C-O activation/C-C bond forming reaction, and amide-directed C-O activation/hydrodemethoxylation reactions under a simple RuH2(CO)(PPh3)3/toluene catalytic system. Of these, the amide-directed C-H activation/cross coupling reaction proceeds well but uniquely on furan 3-amide substrates while the ester-directed C-O activation is effective on the 2-MeO-1-naphthoic acid methyl ester. On the other hand, the amide-directed C-N and C-O activation/coupling reactions are broadly applicable on benzamides and naphthamides. All of these achievements of directed C-H, C-N, C-O activation/coupling reactions complement and may supercede the DoM (directed ortho metalation)-cross coupling strategy, and establish the catalytic base-free DoM-cross coupling process at non-cryogenic temperature as a convenient, economical and green alternative. The new catalytic amide-directed ortho-hydrodemethoxylation reaction has potential value in links to aromatic electrophilic substitution and DoM chemistries. Furthermore, a new borylation reaction via Ru-catalyzed amide-directed C-H activation/C-B bond forming process is also reported herein.Thesis (Ph.D, Chemistry) -- Queen's University, 2010-12-21 11:12:35.564
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Azek, Emna. "Étude mécanistique computationnelle des réactions d’amination catalysées par des dimères de rhodium." Thesis, 2020. http://hdl.handle.net/1866/24764.
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Catalytic amination reactions are a powerful tool in organic synthesis. They aim to introduce nitrogen atom to alkane, alkene or thioether moieties, giving rise to amine products that have various medical and industrial applications. The Lebel group has developed catalytic amination reactions in the presence of rhodium dimers using N-sulfonyloxycarbamates as nitrene precursors. In the presence of a base, N-sulfonyloxycarbamates presumably afforded rhodium nitrenes which underwent C-H insertions, C=C additions or reactions with the sulfur atom of thioethers resulting in acyclic and cyclic carbamates, aziridines and sulfilimines respectively. In addition, good diastereoselectivities were observed in the presence of a chiral N-sulfonyloxycarbamate reagent and a chiral rhodium dimer for all three reactions.
In this dissertation, we are interested in the mechanistic aspects of these amination reactions. Given the absence of experimental proofs of in-situ generated rhodium nitrene species, playing the role of the amination agent, nor of its precomplex, the rhodium nitrenoid, the different amination reactions mechanisms remain uncertain. Our approach is based on the scan of the potential energy surfaces of different mechanistic paths, for each of the amination reactions, well established on the experimental level, by resorting to the Functional Theory of Density (DFT).
The Ernzerhof research group is expert on the development of exchange-correlation functionals, therefore relevant strict criteria have been considered when choosing and validating the theoretical model used during the mechanistic studies. The correlation exchange functional developed by Perdew-Burke-Ernzerhof (PBE) was established as the best to study reactions involving rhodium dimers where the electronic correlation is strong. We studied the formation and reactivity of rhodium nitrene species considering their two lower energy spin states. Singlet rhodium nitrenes appeared to be the most reactive intermediates for the C-H amination reaction. In addition, singlet rhodium nitrenes were shown responsible for the formation of secondary products such as carbonyls and primary carbamates derived from the corresponding N-mesyloxycarbamates. In sharp contrast, in the aziridination reaction, both singlet and triplet rhodium nitrene species acted as aminating agents in a process involving an intersystem spin crossover. To further rationalize the asymmetric induction of catalytic aziridination reactions, we have undertaken the calculation of the diastereoselectivity ratios in the presence of the chiral catalyst Rh2[(S)-nttl]4. An exhaustive study was performed and it revealed that the asymmetric induction was due to a reactive conformation of rhodium nitrene species in which the ligand adopts C4 symmetry.
Up to now, no mechanistic study involving DFT calculations have been reported in the literature for the amination of thioethers, no matter what catalytic system is used. To study catalytic sulfimidation reactions, we calculated the different mechanistic paths of rhodium catalyzed thioanisole imidation with and without DMAP and bis(DMAP)CH2Cl2 additives. The study showed a 'classical' insertion mechanism of rhodium nitrene species into the thioether in absence of bis(DMAP)CH2Cl2. In the presence of the latter, the mechanism diverged to a thioether insertion/salt (bis(DMAP)CH2Cl-OMs) elimination reaction where the rhodium nitrenoid complex was, henceforth, the imidation reagent.Les réactions d’amination catalytiques sont un outil très efficace en synthèse organique. Elles consistent à introduire un azote sur différents composés organiques, permettant de synthétiser des produits aminés qui peuvent être utilisés pour différentes applications médicales et industrielles. Le groupe de recherche du Pr Lebel a développé des réactions d’amination faisant appel aux dimères de rhodium comme catalyseurs et en utilisant les Nsulfonyloxycarbamates, comme précurseurs de nitrènes métalliques. En effet, en présence d’une base, les N-sulfonyloxycarbamates forment possiblement un intermédiaire de type nitrène de rhodium qui peuvent s’insérer dans un lien C-H, s’additionner sur un lien C=C ou réagir avec un atome de soufre d’un thioéther. On peut ainsi préparer des carbamates cycliques et acycliques, des aziridines et des sulfilimines respectivement. Dans le cas où les réactions d’amination sont catalysées par des dimères de rhodium chiraux, on obtient de bonnes diastéréosélectivités en présence d’un réactif N-sulfonyloxycarbamate chiral. Dans cette dissertation, nous nous sommes intéressés aux aspects mécanistiques de ces réactions d’amination. À défaut de preuves expérimentales solides pour prouver la génération in-situ des espèces nitrènes de rhodium, lesquelles sont les agents d’amination clés, ni de celle du pré-complexe, nitrénoïde de rhodium, des incertitudes subsistaient toujours concernant les mécanismes des différentes réactions d’amination. Notre approche se base sur l’étude des surfaces d’énergies potentielles de différents chemins mécanistiques possibles pour chacune des réactions d’amination, bien établie sur le plan expérimental, en faisant recours à la Théorie des Fonctionnelles de la Densité (DFT). Le groupe de recherche du Pr Ernzerhof est expert dans le développement des fonctionnelles d’échange-corrélation. Pour ce, des critères strictes et pertinents ont été pris en compte lors du choix et de la validation du modèle théorique utilisé dans ces études mécanistiques. La fonctionnelle d’échange corrélation développée par Perdew–Burke– Ernzerhof (PBE) s’est révélé être la meilleure pour décrire ces systèmes réactionnels faisant intervenir les dimères de rhodium dont la corrélation électronique est forte. À l’aide de cette fonctionnelle pure, nous avons étudié la formation et la réactivité des espèces nitrènes de rhodium en fonction de leurs deux états de spin de plus basse énergie. Les nitrènes de rhodium singulet se sont révélés être les intermédiaires les plus réactifs dans l`amination de liens C-H. De plus, les nitrènes de rhodium à l’état singulet sont responsables de la formation des produits secondaires tels que les carbonyles et les carbamates primaires dérivés des Nmésyloxycarbamates correspondants. Dans la réaction d’aziridination, les espèces nitrènes de rhodium à l’état singulet et triplet peuvent toutes les deux agir comme agents d'amination et les processus font intervenir un croisement intersystème de spin. Afin de rationaliser l’induction asymétrique des réactions d’aziridination catalytiques, nous avons entrepris le calcul des ratios de diastéréosélectivités en présence du catalyseur chiral Rh2[(S)-nttl]4. L’étude exhaustive de cette réaction a permis de déterminer que l’induction asymétrique provient d’une conformation réactive de l’espèce nitrène de rhodium de symétrie C4. Aucune étude mécanistique s’appuyant sur la chimie computationnelle n’a été rapportée dans la littérature pour la réaction d’amination de thioéthers et ce peu importe le système catalytique. Afin d’étudier les réactions de sulfimidation catalytiques, nous avons calculé les différents chemins mécanistiques de l’imidation du thioanisole catalysée par un complexe de rhodium avec et sans les additifs DMAP et bis(DMAP)CH2Cl2. L’étude montre que le mécanisme procède via une insertion ‘classique’ des espèces nitrènes de rhodium dans le thioéther en absence de bis(DMAP)CH2Cl2. En présence de ce dernier, le mécanisme diverge vers une réaction d’insertion du thioéther/élimination d’un sel (bis(DMAP)CH2Cl-OMs) où le complexe nitrénoïde de rhodium devient, désormais, l’agent d’imidation.