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1
Allart, Eric A. "Metal-promoted [3+2] and [4+2] cycloaddition reactions." Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/33615.
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Dicobalt complexes have been extensively used in synthetic chemistry to protect triple bonds, to form new carbon/carbon bonds using the Nicholas reaction and to form polycyclic molecules using the Pauson-Khand reaction. Using these dicobalt complexes, the formation of new carbon-heteroatom bonds was developed through [3+2] and [4+2] cycloaddition reactions via a stabilised dipole intermediate. Initial work carried out makes use of cyclopropanes substituted with a metal-alkyne complex towards the synthesis of tetrahydrofurans and pyrrolidines in good yields and with acceptable diastereoselectivity. The initial aim of the work described hereafter was to improve and expand the previous work carried out within the group. An alternative route using dihydrofurans as a cyclopropane surrogate was explored as well as other methods to form the cyclopropane in a-position to the alkyne. To extend the scope of the methodology, [4+2] cycloaddition reactions have been explored, using Nicholas carbocation. Various precursors have been prepared using a Knoevenagel condensation or an ene reaction. For the first time in synthetic chemistry, a novel [4+2] dipolar cycloaddition reaction from a cyclobutane has been developed. This reaction has opened a new way for the synthesis of six-membered heterocycles in a totally diastereoselective fashion using cyclobutane cores as precursors. A wide range of aldehydes was used as trapping reagents to form tetrahydropyrans in good yields up to 95% and with a good to total diastereoselectivity proven by nOe and X-Ray analyses. The use of other reagents such as ketones, imines and alkenes has been investigated· towards the formation of new six-membered rings as an extension of the methodology.
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Allen, Jacqueline Y. "Asymmetric [3+2] cycloaddition reactions : new chemistry for solid phase." Thesis, Kingston University, 2003. http://eprints.kingston.ac.uk/20709/.
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The aim of this project was to investigate new asymmetric chemistry for solid phase syntheses where in comparison to solution phase reactions very few solid phase reactions are in general use. The first part of the project involved the synthesis and radical cleavage of a Barton ester to provide a traceless linker on the final reaction product. The synthesis of the Barton ester from benzoylglycine was not successful as the acid chloride derivative of benzolyglycine appeared to undergo a facile cyclisation reaction. In contrast the acid chlorides of both indole-3-acetic acid and N-methylindole-3-acetic acid' were successfully reacted with N-hydroxypyridine-2-thione to give Barton esters and immediate radical cleavage gave the corresponding indole derivatives. The yields of the indole reactions remained low despite our attempts at optimisation and it was therefore concluded that a pyridine-z-thione ester was an unstable linker for successful solid phase chemistry. The second part of the project involved the synthesis of isoxazolidines using [3 + 2] cycloaddition reactions. These compounds have been shown to be useful intermediates in the synthesis of natural products, antibiotics and other medicinally important compounds. Initially model [3 + 2] cycloaddition reactions were carried out to investigate the regio- and stereoselectivity of the reaction. Analysis of several IH_NMR spectra showed broad resonance splitting patterns, attributed to the inversion of the trivalent nitrogen atom, which was investigated by high temperature IH_NMR. Reactions with the N-(methylene)methylamine N-oxide nitrone simplified spectral analysis. Asymmetric [3 + 2] cycloaddition reactions were then carried out between the N-(benzylidene)methylamine N-oxide (and the nitro, chloro and bromo derivatives) with the acryloyl and crotonyl acylated Evans' chiral auxiliaries. The reaction between N-(p-nitrobenzylidene )methylamin~ N-oxide and the acryloyl chiral auxiliary derivative was unsuccessful due to polymerisation of the chiral auxiliary, whilst those between the nitrones and the crotonyl chiral auxiliary derivative gave regiochemical data "but the stereochemical data could not be determined due to the overlapping of resonances on the IH_NMR spectrum. Analysis of the IH_NMR spectra of alternative [3 + 2] cycloaddition products from reactions with the nitrone N-(methylene)methylainine N-oxide were again thwarted by inversion of the nitrogen atom whereas in a [3 + 2] cycloaddition reaction between N-(p-nitrobenzylidene)-methylamine N-oxide and the methacryloyl chiral auxiliary derivative an X-ray analysis of the major diastereomer was obtained. This confirmed the absolute stereochemistry to be (S)-( - )-4:.benzyl-N-[ (S)-5-carbonyl-N,5-dimethyl-(R)-3-(p-nitrophenyl)isoxazolidine ]-2-oxazolidinone (SSR). An attempt was then carried out to transfer this chemistry on to solid supports using Merrifield resin. Purification of the resulting isoxazolidine led to an interesting decarboxylation reaction. Finally, initial investigations into [3 + 2] cycloaddition reactions with electron poor 1,2-disubstituted alkynes were carried out.
3
Ahmed, Awais. "[4+2] and [4+3] cycloaddition reactions and Lewis acid catalysed cycloisomerisation of malonyl epoxides." Thesis, Loughborough University, 2003. https://dspace.lboro.ac.uk/2134/12572.
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Donor-acceptor cyclopropanes have been extensively used in synthetic chemistry in [3+2] and [3+3] cycloaddition reactions for the preparation of highly substituted carbo- and heterocyclic products. This methodology is further extended to donor-acceptor cyclobutane in [4+2] and [4+3] cycloaddition reactions for the synthesis of highly substituted carbo- and heterocyclic products. Initial work carried out makes use of cyclobutanes substituted with a metal-alkyne complex towards the synthesis of tetrahydropyrans in good yields and with acceptable diastereoselectivity. The initial aim of the project was to improve and expand the scope of the previous work carried out within the group on [4+2] cycloaddition reaction. For example, [4+2] and [4+3] cycloaddition reaction were carried out by using diester cyclobutanes having an alkene and phenyl π-donors. The [4+3] cycloaddition reaction of cyclobutane with nitrone did not work but [4+2] cycloaddition was successful when aldehydes were used as trapping reagents. Lower yields of the cycloadducts were observed due to formation of (±)-dimethyl-2-methyl-6-phenylcyclohex-3-ene-1,1-dicarboxylate and 2,6-diphenyl-4,8-dipropenylcyclooctane-1,1,5,5-tetracarboxylic acid tetramethyl ester. During the synthesis of a precursor cyclobutane a novel cycloisomerisation of malonyl epoxide under Lewis acidic conditions to 6,8-dioxabicyclo[3.2.1]octane derivatives was developed. This reaction has opened a new pathway for the synthesis of 6,8-dioxabicyclo[3.2.1]octanes in a diastereoselective fashion using malonyl epoxides as precursors. A wide range of malonyl epoxides were cycloisomerised under Lewis acidic conditions and the cycloisomerisation of syn and anti malonyl epoxides were stereospecific. The diastereoselectivity of the process was proven by nOe and X-ray analysis. The cycloisomerisation of malonyl diepoxide has also been investigated towards the formation of 5,5-dimethoxy-6,6,8,8-tetraoxa4,4-spirobi[bicyclo[3.2.1]octane].
4
Jha, Jay Shankar. "[3+2] Cycloaddition Reaction of Gem-Dicyanoepoxide and Electrophilic Reaction of Ethyl Atropate." Thesis, Southern Illinois University at Edwardsville, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1545300.
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<p> The epoxide-olefin [3+2] cycloaddition reaction is an important tool in synthesizing heterocyclic five member rings. Such cyclic compounds are well known for the formation of biologically active compounds. In this experiment, we developed a method for a [3+2] cycloaddition reaction between gem-dicyano phenyl epoxide and diethyl (E)-2-fluoromaleate to synthesize 2, 2-dicyano-3, 4-diethoxycarbonyl-4-fluoro-5-phenylfuran. The yield of the product was 55.56 %. </p><p> Fluorine is small in size and is the most electronegative element. These properties of fluorine make its incorporation into drugs easy and also increase the efficacy and selectivity of the drugs. Atropic acid has wide applications as an antagonist. The non-fluorinated atropic acid derivative binds to glycine binding sites, which help in the treatment of a number of disease states. Moreover, its derivatives are used in the preservation of beverages, pests control agents and fungicides. Considering the above facts, fluorination of ethyl atropate using XeF<sub>2</sub> via an electrophilic addition reaction in the presence of compounds like I<sub>2</sub>, Se<sub>2</sub>Ph<sub> 2</sub> and S2Ph<sub>2</sub> was performed. The percentage yield of addition products were fairly high, ranging from 63 % to 67 %.</p>
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Dzwiniel, Trevor L. "Seven-membered carbocycle synthesis by cobalt-mediated [3 + 2 + 2] allyl/alkyne cycloaddition reactions and novel [5 + 2] cyclopentadiene/alkyne ring expansions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0033/NQ46833.pdf.
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Griffin, Karen. "Lewis acid-promoted (3+2) cycloadditions and multi-component reactions of methyleneaziridines." Thesis, University of Warwick, 2011. http://wrap.warwick.ac.uk/45241/.
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This thesis describes our attempts towards realising new chemistry involving methyleneaziridines, for the main part, focusing on novel cycloaddition reactions involving this unique, densely functionalised heterocycle. Contrary to methyleneaziridines, the cycloaddition reactions of aziridines have been extensively studied. Thus, chapter one presents an introduction and literature review of cycloaddition reactions involving the aziridine nucleus, in order to contextualise the research described in chapter two. Chapter two describes the discovery and development of a novel Lewis acidpromoted (3+2) cycloaddition reaction of methyleneaziridines onto alkyne and alkene acceptors. Both inter- and intramolecular variants of this methodology were examined. The latter substrates being readily made by functionalisation of the parent methyleneaziridines through an efficient lithiation/alkylation sequence. These cycloadditions most likely proceed in a stepwise manner through opening of the methyleneaziridine by the nucleophilic alkene (or alkyne) and subsequent ring closure of the nitrogen atom onto the resultant carbocation. This chemistry provides a powerful new approach to a variety of heterocyclic systems including highly functionalised pyrroles and pyrrolidines. Chapter three begins with a brief introduction to multicomponent reactions, focusing on those which incorporate the methyleneaziridine nucleus. Our efforts towards realising new multicomponent reactions involving methyleneaziridines are detailed. Specifically, the attempted syntheses of 3,4-dihydro-1(2H)-isoquinolones, α-fluorinated and N-t-butylsulfinyl ketimines are described. Chapter four details the experimental procedure and characterisation data for the novel compounds produced in this thesis.
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PAPARIN, JEAN-LAURENT. "Developpement des reactions de cycloaddition 4 + 2 et 4 + 3 pour la preparation d'heterocycles azotes originaux utilisables en chimie combinatoire." Rennes 1, 1999. http://www.theses.fr/1999REN10192.
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Le travail presente dans ce memoire concerne la synthese de nouveaux scaffolds utilisables en chimie combinatoire. Une etude de la reaction d'aza diels-alder thermique de 1,4-bis aryl-2-aza-1,3-butadienes et de dienophiles deficients en electron a ete realisee. Les 2,5-bis aryl-pyridines cibles ont ete obtenues avec des rendements modestes. Une reaction competitive de dimerisation de l'azadiene a ete mise en evidence dans certains cas. Une etude de la reaction de cycloaddition 4 + 3 de diverses ,'-dibromocetones avec le n-carbomethoxypyrrole puis le n-carbomethoxy-2-(1',3'-dioxolan-2'-yl)-pyrrole en presence de diethylzinc a ete realisee. Cette reaction a ensuite ete etendue aux n-boc-pyrroles pour permettre l'obtention de scaffolds porteurs de groupements protecteurs deprotegeables selectivement. A l'exception de la reaction des 1,3-bis aryl-1,3-dibromo-propan-2-one, les cycloadduits ont ete obtenus avec de bons rendements et de tres bonnes selectivites. Des reactions d'aldolisation et d'alkylation en du carbonyle ainsi que des reactions d'addition nucleophile sur le carbonyle ont ete effectuees. L'ensemble de ces resultats montre que la plupart des atomes de ce squelette sont fonctionnalisables. Une etude preliminaire de la synthese d'un scaffold polyfonctionnalisable a partir de la 2,4-dibromo-1,5-bis (4-tert-butyldiphenylsilyloxyphenyl)-pentan-3-one a ete realisee.
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Liang, Shengwen. "Nitrene Transfer Reactions Mediated by Transition Metal Scorpionate Complexes." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1339005115.
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Salt, Michael C. "A kinetic and mechanistic investigation of phosphonium salt hydrolysis and synthetic studies on the cycloaddition reactions of 2-(3-chloropropenyl) phosphonic dichloride." Thesis, Staffordshire University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387482.
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Rodier, Fabien. "Nouvel accès chimio-, régio- et stéréosélectif aux motifs spirolactones polycycliques via une réaction de cycloaddition [3+2]." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4324.
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Le système spirocyclique (7,5) est un motif récurrent dans un certain nombre de produits naturels tels que les Micrandilactones ou les Rubriflordilactones. Ces structures polycycliques représentent un réel défi synthétique pour les chimistes organiciens puisqu'elles présentent au moins neuf centres stéréogènes dont plusieurs sont quaternaires. L'objectif principal de ce travail était de développer de nouvelles réactions de cycloaddition [3+2] et de les utiliser comme étape clé afin d'obtenir rapidement et efficacement le squelette polycylique de ces composés. La première partie de ces travaux a été consacrée au développement d'une réaction de cycloaddition [3+2] intra- et intermoléculaire mettant un jeu un nouveau partenaire dipolarophile, les γ-alkylidènes-buténolides. Cette étape clé conduit à la formation de cycloadduits hautement fonctionnalisés de façon rapide et efficace avec d'excellents rendements et de façon hautement chimio-, régio- et diastéréosélective. De plus, des calculs théoriques ont permis d'appréhender le mécanisme réactionnel entre un 2-diazo-1,3-cétoester et la protoanémonine catalysé par un sel de rhodium mis en jeu dans ce type de processus et ainsi d'expliquer les résultats obtenus.Dans une deuxième partie, deux approches aux cœurs ABC et CD de la micrandilactone C ont été développées mettant respectivement en jeu une cycloaddition [3+2] formellement intermoléculaire utilisant un lien de type acétal de silicium et suivie par une réaction de Diels Alder. Ainsi, le motif tétracyclique devrait être rapidement accessible après quelques aménagements de la voie de synthèse initiale<br>The spiro (7, 5) ring system is a recurring structural moiety in numerous natural products such as Micrandilactones and Rubriflordilactones. In term of complexity, these polycyclic structures represent a synthetic challenge for organic chemist. Indeed, these molecules present at least nine stereogenic centres including several quaternary ones. The main goal of this work was to use unprecedented partners in the [3+2] cycloaddition reaction to obtain quickly and efficiently the polycyclic core of those natural products. The first part of these studies was dedicated to the development of an intra- and intermolecular [3+2] cycloaddition using for the first time a γ-alkylidene-butenolide dipolarophile. This approach provides rapid and facile access to highly functionalised polycyclic molecules along with excellent regio-, chemo- and stereoselectivities. In addition, thanks to computational studies an overall picture of the mechanism of the intermolecular rhodium catalysed [3+2] cycloaddition between 2-diazo-1,3-ketoester and protoanemonin was apprehended, and experimental results have been rationalised.Finally, two approaches to the ABC and CD cores of Micrandilactone C were developed using respectively a formal intermolecular [3+2] cycloaddition reaction in presence of a silicon acetal linker followed by a Diels Alder reaction. The ACDE tetracyclic moiety should be quickly accessible after few modifications of the initial strategy
11
Rodier, Fabien. "Nouvel accès chimio-, régio- et stéréosélectif aux motifs spirolactones polycycliques via une réaction de cycloaddition [3+2]." Electronic Thesis or Diss., Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4324.
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Le système spirocyclique (7,5) est un motif récurrent dans un certain nombre de produits naturels tels que les Micrandilactones ou les Rubriflordilactones. Ces structures polycycliques représentent un réel défi synthétique pour les chimistes organiciens puisqu'elles présentent au moins neuf centres stéréogènes dont plusieurs sont quaternaires. L'objectif principal de ce travail était de développer de nouvelles réactions de cycloaddition [3+2] et de les utiliser comme étape clé afin d'obtenir rapidement et efficacement le squelette polycylique de ces composés. La première partie de ces travaux a été consacrée au développement d'une réaction de cycloaddition [3+2] intra- et intermoléculaire mettant un jeu un nouveau partenaire dipolarophile, les γ-alkylidènes-buténolides. Cette étape clé conduit à la formation de cycloadduits hautement fonctionnalisés de façon rapide et efficace avec d'excellents rendements et de façon hautement chimio-, régio- et diastéréosélective. De plus, des calculs théoriques ont permis d'appréhender le mécanisme réactionnel entre un 2-diazo-1,3-cétoester et la protoanémonine catalysé par un sel de rhodium mis en jeu dans ce type de processus et ainsi d'expliquer les résultats obtenus.Dans une deuxième partie, deux approches aux cœurs ABC et CD de la micrandilactone C ont été développées mettant respectivement en jeu une cycloaddition [3+2] formellement intermoléculaire utilisant un lien de type acétal de silicium et suivie par une réaction de Diels Alder. Ainsi, le motif tétracyclique devrait être rapidement accessible après quelques aménagements de la voie de synthèse initiale<br>The spiro (7, 5) ring system is a recurring structural moiety in numerous natural products such as Micrandilactones and Rubriflordilactones. In term of complexity, these polycyclic structures represent a synthetic challenge for organic chemist. Indeed, these molecules present at least nine stereogenic centres including several quaternary ones. The main goal of this work was to use unprecedented partners in the [3+2] cycloaddition reaction to obtain quickly and efficiently the polycyclic core of those natural products. The first part of these studies was dedicated to the development of an intra- and intermolecular [3+2] cycloaddition using for the first time a γ-alkylidene-butenolide dipolarophile. This approach provides rapid and facile access to highly functionalised polycyclic molecules along with excellent regio-, chemo- and stereoselectivities. In addition, thanks to computational studies an overall picture of the mechanism of the intermolecular rhodium catalysed [3+2] cycloaddition between 2-diazo-1,3-ketoester and protoanemonin was apprehended, and experimental results have been rationalised.Finally, two approaches to the ABC and CD cores of Micrandilactone C were developed using respectively a formal intermolecular [3+2] cycloaddition reaction in presence of a silicon acetal linker followed by a Diels Alder reaction. The ACDE tetracyclic moiety should be quickly accessible after few modifications of the initial strategy
12
Compain-Batissou, Cudel Muriel. "SYNTHESE DE NOUVELLES QUINONES HETEROCYCLIQUES PAR APPLICATION DES REACTIONS DE CYCLOADDITIONS DE DIELS-ALDER ET 1,3-DIPOLAIRE. EVALUATION IN VITRO DE LEUR ACTIVITE SUR TOXOPLASMA GONDII." Phd thesis, Université Claude Bernard - Lyon I, 2007. http://tel.archives-ouvertes.fr/tel-00281991.
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La toxoplasmose est une anthropozoonose ubiquitaire causée par Toxoplasma gondii. Malgré de nombreuses recherches, l'arsenal thérapeutique reste très restreint. L'objectif des travaux présentés dans ce mémoire est la synthèse de carbazolequinones et l'évaluation de leur efficacité sur T. gondii. Les carbazolequinones naturelles comme les calothrixines ont des propriétés antiparasitaires et cytotoxiques. La synthèse de para- et ortho-quinones de type benzo-, isoxazolo- et triazolo-carbazolequinones a été réalisée par application des réactions de cycloaddition [4+2] ou 1,3-dipolaires régiosélectives. La stratégie de synthèse à partir de dipolarophiles monobromés permet en effet, d'accéder sélectivement au régioisomère souhaité. Les attributions de structure des régiosiomères ont été confirmées par RMN 1H NOE et par une étude des corrélations 1H -13C HMBC. Concernant l'évaluation biologique in vitro, les composés inhibent la croissance de T. gondii comme la sulfadiazine et la pyriméthamine, avec une cytotoxicité sur les cellules myélomonocytiques THP1. Aucun des composés synthétisés n'inhibent la PNP, enzyme clé de la voie de sauvetage des purines, seule voie d'accès pour le parasite aux bases puriques. L'inhibition de la croissance de T. gondii par nos composés n'est pas liée directement liée à l'inhibition de la PNP.
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Schmitt, Gérard. "Réactions de l'hydrofluoroborate d'un composé de Reissert sur divers alcenes : Compétition entre cycloaddition dipolaire-1,3 et cycloaddition de Diels-Alder." Besançon, 1987. http://www.theses.fr/1987BESA2041.
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KOBAYAKAWA, MASATO. "Etude de la reduction de beta-ceto oxazoline et de reactions de cycloadditions 2+3 inter et intramoleculaires de n-oxydes d'oxazolines." Paris 11, 1992. http://www.theses.fr/1992PA112333.
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Apres avoir decrit differentes methodes de preparation d'une beta-ceto oxazoline enantiomeriquement pure, divers reactions de reduction du groupement cetonique ont ete etudiees. Dans une deuxieme partie, divers oxazolines portant une chaine alkenylee en position 2 sont transformees par oxydation en oxazolidinooxaziridines isomerisees ensuite en n-oxydes d'oxazolines. Ces composes conduisent par des reactions de cycloadditions 2+3 intramoleculaires a des adduits tricycliques avec generalement une bonne regio et stereoselectivite. Un adduit ainsi obtenu a ete hydrogenolyse et hydrolyse fournissant une cyclopentanone fonctionnalisee avec une bonne diastereoselectivite. Ce type de reaction a ete etendu au cas des oxazolines enantiomeriquement pures. Dans le cas d'une reaction de cycloaddition intramoleculaire on obtient bien l'adduit attendu un seul isomere se forme dans cette reaction. La version intermoleculaire de cette cycloaddition conduit toutefois a des produits d'addition de michael apres hydrolyse spontanee du n-oxyde d'oxazoline
15
Berndt, Christian. "Bildungstendenz und Reaktionen von α-Azidoalkoholen". Doctoral thesis, Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-112553.
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Gegenstand der vorliegenden Arbeit ist die Synthese von α-Azidoalkoholen durch die Reaktion von aliphatischen sowie aromatischen Aldehyden mit Stickstoffwasserstoffsäure. Dabei stellt sich ein Gleichgewicht ein, dessen Lage durch die Ermittlung der Gleichgewichtskonstanten quantitativ bestimmt wird. In jedem Fall besteht die Möglichkeit, den α-Azidoalkohol in der Gleichgewichtsmischung zu charakterisieren und teilweise gelingt die Isolierung der reinen α-Azidoalkohole bei tiefen Temperaturen sowie deren Charakterisierung mittels Tieftemperatur-NMR-Spektroskopie. Die Ausgangsaldehyde für die Synthese der α-Azidoalkohole besitzen elektronenschiebende oder elektronenziehende Substituenten oder sind prochiral oder besitzen funktionelle Gruppe für intramolekulare Reaktionen. Die Titelverbindungen werden mit Cyclooctin im Sinne einer 1,3-dipolaren Cycloaddition abgefangen oder mit Carbonsäurechloriden in die entsprechenden Ester der α-Azidoalkohole überführt. Das nur aus theoretischen Arbeiten bekannte Formylazid wird erstmals aus den α-Azidoalkoholen durch Oxidation hergestellt und in Lösung vollständig charakterisiert. Es werden zudem zahlreiche Alternativsynthesen für Formylazid erfolgreich durchgeführt.
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姚大源 and Tai-yuen Yue. "Cycloaddition reactions of 2-vinylchromones." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1992. http://hub.hku.hk/bib/B31210661.
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Wan, Honghe. "Allenes and (2+2+1) cycloaddition reactions." Morgantown, W. Va. : [West Virginia University Libraries], 1998. http://etd.wvu.edu/templates/showETD.cfm?recnum=195.
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Thesis (M.S.)--West Virginia University, 1998.<br>Title from document title page. Document formatted into pages; contains xii, 99 p. : ill. Includes abstract. Includes bibliographical references (p. 93-99).
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Haraburda, Ewelina. "[2+2+2] cycloaddition reactions involving allenes catalysed by rhodium." Doctoral thesis, Universitat de Girona, 2015. http://hdl.handle.net/10803/328439.
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The development of new chemical processes for the formation of carbon-carbon bonds is an important topic in organic chemistry. In particular, the transition metal catalysed [2+2+2] cycloaddition reaction is a highly efficient synthetic tool that allows six-membered polysubstituted carbo- and heterocyclic derivatives to be obtained in an atom economy process. Allenes are versatile substrates for cycloaddition reactions that provide a good reactivity profile together with the ability to increase the stereochemical complexity of the cycloadducts obtained. This doctoral thesis, divided into seven different chapters, is based on the methodological study of the rhodium(I)-catalysed [2+2+2] cycloaddition reaction involving allenes. Chapter 1 contains a general introduction to the structural and reactivity particularities of allenes and to the [2+2+2] cycloaddition reactions, making reference to the main examples found in the literature. Chapter 2 sets out the general objectives of the thesis. In Chapters 3 and 4 the reactivity of linear chiral and non-chiral allene-ene/yne-allene substrates in totally intramolecular rhodium-catalysed [2+2+2] cycloaddition is evaluated. In Chapter 5, a dehydrogenative [2+2+2] cycloaddition of cyano-yne-allene substrates is developed which allows for the synthesis of the 2,6-naphthyridines core found in biologically relevant products. Chapter 6 draws general conclusions from the results of these studies. Finally, Chapter 7 contains the experimental procedure and the characterization data for the compounds synthesised in this thesis.<br>El desarrollo de nuevos procesos químicos para la formación de enlaces carbono-carbono es un campo importante en química orgánica. Concretamente, la reacción de cicloaddición [2+2+2] catalizada por metales de transición es una herramienta muy eficiente que permite la formación de derivados carbo- y heterocíclicos polisustituidos de seis miembros en un proceso de economía atómica. Por otro lado, los alenos son sustratos versátiles en reacciones de cicloadición que además de poseer un buen perfil de reactividad tienen la habilidad de incrementar la complejidad estructural en los cicloaductos que permiten sintetizar. La presente tesis doctoral, dividida en siete capítulos, se ha basado en el estudio metodológico de cicloadiciones [2+2+2] catalizadas por rodio(I) involucrando alenos. El Capítulo 1 contiene una introducción general a las particularidades estructurales y de reactividad de los alenos y a las reacciones de cicloadición [2+2+2] haciendo referencia a los principales ejemplos descritos en la bibliografía. El Capítulo 2 presenta los objetivos generales de la tesis. En los Capítulos 3 y 4 se describe la reactividad de sustratos lineales aleno-eno/yno-aleno en forma aquiral o quiral en la reacción totalmente intramolecular de la cicloadición [2+2+2] catalizada por rodio(I). El Capítulo 5 desarrolla una reacción de cicloadición [2+2+2] deshidrogenativa de sustratos ciano-yno-aleno que permite la síntesis de la unidad estructural de 2,6-naftiridina presente en distintos productos biológicamente relevantes. El Capítulo 6 incluye las conclusiones generales que se extraen de la tesis. Por último, el Capítulo 7 contiene el procedimiento experimental y la caracterización de todos los compuestos sintetizados en esta tesis.
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Parera, Briansó Magda. "Transition metal-catalysed [2+2+2] cycloaddition reactions. Methodology and mechanism." Doctoral thesis, Universitat de Girona, 2014. http://hdl.handle.net/10803/145035.
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The transition-metal catalysed [2+2+2] cycloaddition reaction is a highly efficient synthetic tool that allows six-membered polysubstituted carbo- and heterocyclic derivatives to be obtained in an atom economy process. This doctoral thesis is based on methodological and mechanistic studies of the rhodium(I)-catalysed [2+2+2] cycloaddition reaction. In particular, the use of hemilabile S-stereogenic and P-stereogenic ligands for the rhodium-catalysed [2+2+2] cycloaddition is described. The activity of these new catalytic systems is evaluated in the cycloaddition of three alkynes and in the enantioselective cycloaddition of enediynes to obtain chiral cyclohexa-1,3-dienes. Moreover, the participation of Baylis-Hillman adducts as alkene moieties for the partially intramolecular [2+2+2] cycloaddition is described for the synthesis of a set of enantioenriched bicyclic cyclohexadienes featuring a quaternary stereogenic centre. Finally, the mechanistic study of the [2+2+2] cycloaddition of alkynes by electrospray ionization mass spectrometry and DFT calculations is performed.<br>La reacció de cicloaddició [2+2+2] catalitzada per metalls de transició és una eina molt eficient que permet la formació de derivats carbo- i heterocíclics polisubstituïts de sis membres en un procés d’economia atòmica. Aquesta tesi doctoral es basa en l’estudi metodològic i mecanístic de les reaccions de cicloaddició [2+2+2] catalitzades per rodi(I). Concretament, es descriu l’ús de lligands hemilàbils S-estereogènics i P-estereògenics per a la reacció de cicloaddició [2+2+2] catalitzada per rodi d’alquins i també en la cicloaddició enantioselectiva d’endiïns per a l’obtenció de ciclohexadiens quirals. També s’estudia la participació d’adductes de Baylis-Hillman com a substrats olefínics d’aquestes reaccions permetent la síntesi de ciclohexadiens quirals bicíclics amb un centre estereogènic quaternari. Finalment, es presenta l’estudi mecanístic de les reaccions de cicloaddició [2+2+2] d’alquins a través de l’espectrometria de masses amb ionització per electroesprai i càlculs DFT.
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Fernández, Wang Martí. "New challenges in Rh(I)-catalysed [2+2+2] cycloaddition reactions." Doctoral thesis, Universitat de Girona, 2017. http://hdl.handle.net/10803/663661.
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This doctoral thesis studies the involvement of challenging unsaturated substrates in the transition-metal catalysed [2+2+2] cycloaddition reaction, as well as new catalytic systems for the reaction. First, Morita-Baylis-Hillman adducts are involved in the partial intramolecular rhodium(I)-catalysed [2+2+2] cycloaddition reaction. Next, linear chiral allene-yne/ene-allene substrates are synthesized and submitted to [2+2+2] cycloaddition reaction conditions. The process works with effective chirality induction of the chiral centres of the linear compounds to the cycloadducts. Following, the synthesis of a dendrimer by means of a Co-catalysed [2+2+2] cycloaddition reaction to form the core is described. The dendrimer contains a poly(ethylene glycol) moiety, as well as a ligand that can coordinate to a metal. Finally, hybrid silica materials containing rhodium(I) complexes are prepared. These materials are used for the [2+2+2] cycloaddition of alkynes and can be recovered by simple filtration and reused in further reactions.<br>Aquesta tesi doctoral estudia la participació de substrats insaturats complexos en la reacció de cicloaddició [2+2+2] catalitzada per metall de transició, així com nous sistemes catalítics per la reacció. Primer s'utilitzen adductes de Morita-Baylis-Hillman en la reacció de cicloaddició [2+2+2] catalitzada per rodi(I) parcialment intramolecular. Després, es sintetitzen substrats lineals al·lè-í/è-al·lè quirals i es sotmeten a condicions de cicloaddició [2+2+2]. El procés dóna lloc a una inducció quiral dels centres quirals dels compostos lineals cap els cicloadductes. A continuació, es descriu la síntesi d'un dendrimer mitjançant una cicloaddició [2+2+2] catalitzada per cobalt per formar el cor. El dendrimer conté un residu de polietilé glicol, així com un lligand que pot coordinar a un metall. Finalment, es preparen síliques híbrides que contenen complexos de rodi(I). Aquests materials s'utilitzen en la cicloaddició [2+2+2] d'alquins i es poden recuperar per simple filtració i reutilitzar en pròximes reaccions.
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Dachs, Soler Anna. "Rhodium(I) catalyzed [2+2+2] cycloaddition reactions: experimental and theoretical studies." Doctoral thesis, Universitat de Girona, 2011. http://hdl.handle.net/10803/52981.
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The [2+2+2] cycloaddition reaction involves the formation of three carbon-carbon bonds in one single step using alkynes, alkenes, nitriles, carbonyls and other unsaturated reagents as reactants. This is one of the most elegant methods for the construction of polycyclic aromatic compounds and heteroaromatic, which have important academic and industrial uses. The thesis is divided into ten chapters including six related publications. The first study based on the Wilkinson’s catalyst, RhCl(PPh3)3, compares the reaction mechanism of the [2+2+2] cycloaddition process of acetylene with the cycloaddition obtained for the model of the complex, RhCl(PH3)3. In an attempt to reduce computational costs in DFT studies, this research project aimed to substitute PPh3 ligands for PH3, despite the electronic and steric effects produced by PPh3 ligands being significantly different to those created by PH3 ones. In this first study, detailed theoretical calculations were performed to determine the reaction mechanism of the two complexes. Despite some differences being detected, it was found that modelling PPh3 by PH3 in the catalyst helps to reduce the computational cost significantly while at the same time providing qualitatively acceptable results. Taking into account the results obtained in this earlier study, the model of the Wilkinson’s catalyst, RhCl(PH3)3, was applied to study different [2+2+2] cycloaddition reactions with unsaturated systems conducted in the laboratory. Our research group found that in the case of totally closed systems, specifically 15- and 25-membered azamacrocycles can afford benzenic compounds, except in the case of 20-membered azamacrocycle (20-MAA) which was inactive with the Wilkinson’s catalyst. In this study, theoretical calculations allowed to determine the origin of the different reactivity of the 20-MAA, where it was found that the activation barrier of the oxidative addition of two alkynes is higher than those obtained for the 15- and 25-membered macrocycles. This barrier was attributed primarily to the interaction energy, which corresponds to the energy that is released when the two deformed reagents interact in the transition state. The main factor that helped to provide an explanation to the different reactivity observed was that the 20-MAA had a more stable and delocalized HOMO orbital in the oxidative addition step. Moreover, we observed that the formation of a strained ten-membered ring during the cycloaddition of 20-MAA presents significant steric hindrance. Furthermore, in Chapter 5, an electrochemical study is presented in collaboration with Prof. Anny Jutand from Paris. This work allowed studying the main steps of the catalytic cycle of the [2+2+2] cycloaddition reaction between diynes with a monoalkyne. First kinetic data were obtained of the [2+2+2] cycloaddition process catalyzed by the Wilkinson’s catalyst, where it was observed that the rate-determining step of the reaction can change depending on the structure of the starting reagents. In the case of the [2+2+2] cycloaddition reaction involving two alkynes and one alkene in the same molecule (enediynes), it is well known that the oxidative coupling may occur between two alkynes giving the corresponding metallacyclopentadiene, or between one alkyne and the alkene affording the metallacyclopentene complex. Wilkinson’s model was used in DFT calculations to analyze the different factors that may influence in the reaction mechanism. Here it was observed that the cyclic enediynes always prefer the oxidative coupling between two alkynes moieties, while the acyclic cases have different preferences depending on the linker and the substituents used in the alkynes. Moreover, the Wilkinson’s model was used to explain the experimental results achieved in Chapter 7 where the [2+2+2] cycloaddition reaction of enediynes is studied varying the position of the double bond in the starting reagent. It was observed that enediynes type yne-ene-yne preferred the standard [2+2+2] cycloaddition reaction, while enediynes type yne-yne-ene suffered β-hydride elimination followed a reductive elimination of Wilkinson’s catalyst giving cyclohexadiene compounds, which are isomers from those that would be obtained through standard [2+2+2] cycloaddition reactions. Finally, the last chapter of this thesis is based on the use of DFT calculations to determine the reaction mechanism when the macrocycles are treated with transition metals that are inactive to the [2+2+2] cycloaddition reaction, but which are thermally active leading to new polycyclic compounds. Thus, a domino process was described combining an ene reaction and a Diels-Alder cycloaddition.<br>La reacció de cicloaddició consisteix en la formació de tres enllaços carboni-carboni en un únic pas de reacció on poden estar involucrats alquins, alquens, nitrils, carbonils i altres compostos insaturats. És un dels mètodes més elegants per a la construcció de compostos aromàtics i heteroaromatics policíclics amb importants usos acadèmics i industrials. La tesi es divideix en deu capítols que contenen sis publicacions relacionades. El primer estudi es basa en el catalitzador de Wilkinson, RhCl(PPh3)3, on es compara el mecanisme de reacció del procés de cicloaddició d’acetilè pel que s’obté amb el model del complex, RhCl(PH3)3. Aquest projecte de recerca va ser iniciat per estudiar la substitució de lligands PPh3 per PH3 en els estudis de DFT, que s’aplica habitualment per reduir el cost computacional, tot i que els efectes electrònics i estèrics produïts pels lligands PPh3 són molt diferents dels creats per PH3. Malgrat algunes diferències observades, es va constatar que la substitució de PPh3 per PH3 en el catalitzador pot ser utilitzada per reduir el cost computacional de manera significativa i a l’hora obtenir resultats qualitativament acceptables. Un cop obtinguts els resultats anteriors, es va utilitzar el model del catalitzador de Wilkinson, RhCl(PH3)3, per l’estudi teòric de diferents reaccions de cicloaddició amb sistemes insaturats duts a terme al laboratori. En el grup de recerca es va trobar que en el cas de sistemes totalment tancats, concretament els macrocicles de 15 i 25 baules, poden donar sistemes benzènics policíclics excepte en el cas del macrocicle de 20 baules, que va resultar inactiu vers el catalitzador de Wilkinson. En aquest estudi, la realització de càlculs teòrics va permetre determinar l’origen de la diferent reactivitat del macrocicle de 20 baules, on es va trobar que la barrera d’activació de l’addició oxidativa entre dos alquins és molt més alta que les que es van obtenir pel macrocicle de 15 i 25 baules. Aquesta barrera es va atribuir bàsicament a l’energia d’interacció, la qual correspon a l’energia que s’allibera quan els dos reactius deformats interaccionen en l’estat de transició. Concretament el principal factor que hi contribueix és que el macrocicle de 20 baules presenta més estabilitat i més deslocalització de l’orbital HOMO en el pas d’addició oxidativa. A més a més, es va observar que la formació d’anells de 10 baules durant la cicloaddició del macrocicle de 20 baules presenta impediments estèrics importants. Per altra banda, en el Capítol 5 es presenten estudis electroquímics realitzats en col•laboració amb la Prof. Anny Jutand de París, que van permetre estudiar el cicle catalític de la reacció de cicloadició entre un dií i un monoalquí. Es van obtenir així les primeres dades cinètiques dels dos principals passos del cicle catalític amb el complex de Wilkinson, on es va observar que el pas determinant de la reacció pot variar en funció de l’estructura dels reactius de partida. En el cas en què en la reacció de cicloaddició participin dos triples i un doble enllaç en la mateixa molècula (endiins), és conegut que l’addició oxidativa pot donar-se entre dos triples enllaços o un triple i un doble enllaç. El model del catalitzador de Wilkinson va ser utilitzat mitjançant càlculs DFT per analitzar els diferents factors que poden influir en el mecanisme de reacció. Aquí es va observar que els endiins cíclics sempre prefereixen l’addició oxidativa entre els dos triples enllaços, mentre que els acíclics tenen diferent preferència en funció del linker i dels substituents presents en els triples enllaços. A més a més, el mateix model de Wilkinson es va utilitzar per explicar els resultats experimentals realitzats en el Capítol 7 on s’estudia la reacció de cicloaddició d’endiins variant la posició del doble enllaç en el reactiu de partida. Es va observar que els sistemes in-en-in preferien la cicloaddició convencional donant el producte ciclohexadienic esperat, mentre que els sistemes in-in-en patien una β-eliminació seguida d’una eliminació reductiva del catalitzador de Wilkinson i donant, finalment, productes ciclohexadiènics els quals són isòmers dels que s’obtindrien mitjançant una cicloaddició convencional. Finalment, l’últim capítol d’aquesta tesi es basa en l’ús de càlculs DFT per determinar el mecanisme de reacció quan els macrocicles són tractats amb metalls de transició inactius per donar la reacció de cicloaddició, però reaccionen tèrmicament obtenint nous compostos policíclics. Així es va descriure un procés dòmino on es combina una reacció ene seguida d’una cicloaddició de Diels-Alder.
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Lo, Tsz-kiu Brian, and 盧子翹. "Intermolecular [4+3] cycloaddition reactions using epoxy enol silanes." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B45877749.
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Carter, Kevin William. "Methodological and synthetic studies of [4+3] cycloaddition reactions /." free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9842583.
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Linaza, Sabin. "Catalytic properties of antibodies in [4+2] cycloaddition." Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248702.
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Stones, James Alexander. "[4+2] cycloaddition reactions of conformationally restricted tethered trienes." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338511.
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PreÌvost, Natacha. "Radical, alkylation and cycloaddition reactions of a 2-alkylideneaziridines." Thesis, University of Exeter, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273005.
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Viceriat, Audrey. "Cycloaddition [3+2] de cétènes avec des aziridines." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAV049/document.
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Ce travail de thèse a permis de développer un nouveau type de cycloaddition [3+2] des cétènes impliquant des aziridines. Les aziridines sont de bons précurseurs de dipôles 1,3-azotés zwittérioniques, via la coupure sélective de leur liaison C-N par activation avec un acide de Lewis. Nous avons montré qu'en présence d'un cétène et d'iodure de lithium, l'aziridine s'ouvre, et le dipôle 1,3 formé réagit avec le cétène pour offrir des gamma-lactames de manière très efficace. Cette nouvelle cycloaddition [3+2] s'étend à la transformation monotope d'une imine en gamma-lactame, stratégie compatible avec une large gamme d'imines aromatiques et de cétènes stables. Enfin, une synthèse monotope, catalytique et asymétrique de gamma-lactames énantioenrichis a été développée à partir d'oléfines par aziridination asymétrique avec des nitrènes<br>This thesis work focuses on a new type of [3+2] cycloaddition of ketenes with aziridines. Aziridines are good precursors of zwitterionic 1,3-aza-dipoles, by selective C-N bond cleavage catalyzed by Lewis acid. We have found that ketenes react with the 1,3-dipole generated by addition of lithium iodide to the aziridine, efficiently providing the gamma-lactams. This new cycloaddition could be extended to a one-pot simple transformation of imines to gamma-lactams. The synthesis is compatible with a wide range of aromatic imines and stable ketenes. Finally, a one-pot catalytic asymmetric synthesis of enantioenrichied gamma-lactams have been developed starting from olefins, involving an asymmetric nitrene aziridination
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LLERENA, DOMINIQUE. "Reactions de cycloaddition (2+2+2) d'allenediynes catalysees par des complexes du cobalt (i)." Paris 6, 1995. http://www.theses.fr/1995PA066378.
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Des allenediynes diversement substitues, dont les syntheses originales sont decrites ont ete engages avec des quantites stoechiometriques de cpco(co)#2 dans des reactions de cycloaddition (2+2+2). Ces reactions ont permis la synthese de structures tricycliques analogues des cycles abc ou bcd de steroides. Par ailleurs, cette etude a permis de mettre en evidence une nouvelle catalyse de la ene-reaction par le cobalt mettant en jeu des composes allenynes
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Safir, Imad. "Nouvelle synthèse de pyrroles par cycloaddition [3+2] intramoléculaire." Poitiers, 2004. http://www.theses.fr/2004POIT2275.
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La cycloaddition dipolaire-1,3 est devenue un outil synthétique puissant permettant la synthèse d'hétérocycles azotés à cinq chaînons. Dans ce travail nous avons mis au point une nouvelle synthèse de pyrroles par cycloaddition. Nous avons entrepris la synthèse de nombreux pyrroles originaux variés pouvant présenter des propriétés pharmacologiques. La réaction des 2-O- et 2-S-propargylbenzaldéhydes et des amines aliphatiques a-fonctionnelles forme un dipôle qui conduit, après aromatisation, à des benzopyrano- et benzothiopyranopyrroles, alors qu'avec les amines alicycliques nous avons obtenu des benzopyrano- et benzothiopyranopyrrolizines (ou indolizines). Dans le cas des 2-N-propargylbenzaldéhydes, l'étape d'aromatisation est plus complexe et conduit à des pyrroles différents par un mécanisme nouveau. Une extension à d'autres dipolarophiles acétyléniques de type pyrroles-aldéhydes et indoles-aldéhydes a conduit à de nouvelles pyrrolopyrrolizines et pyrrolobenzopyrrolizines ainsi qu'à des pyrrolizinopyrrolizines et pyrrolizinobenzopyrrolizines. Enfin, nous avons utilisé la méthodologie d'activation par micro-ondes pour effectuer ces réactions et nous avons observé une amélioration des rendements et un gain important des temps de réaction<br>The 1,3-dipolar cycloaddition reaction is a powerful synthetic tool permitting the synthesis of five membered nitrogen heterocycles. In this work, we have developed a novel synthesis of pyrroles by cycloaddition. We describe the synthesis of numerous new pyrroles with potential pharmacological properties. The reaction of 2-O- and 2-S-propargylbenzaldéhydes with different amines produces an intermediate azomethine ylide which undergoes cycloaddition, followed by aromatization, to provide benzopyrano- and benzothiopyranopyrroles. With alicyclic amines, benzopyrano- and benzothiopyranopyrrolizines (or indolizines) are obtained. In the case of the 2-N-propargylbenzaldehydes, the aromatisation step is more complex, giving rise to new pyrroles by a new mechanism. An extension to other acetylenic dipolarophiles derived from 2-carboxaldehyde-pyrroles and 2-carboxaldehyde-indoles gave new pyrrolopyrrolizines and pyrrolobenzopyrrolizines as well as pyrrolizinopyrrolizines and pyrrolizinobenzopyrrolizines. Finally, we adapted this methodology to be used under microwaves activation. As a result we observed improved yields and shorter reaction times
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Chakraborty, Bhaskar. "Studies of 1, 3 Dipolar cycloaddition reactions with N- cyclohexyl Nitrones." Thesis, University of North Bengal, 1995. http://hdl.handle.net/123456789/768.
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Aguirre, Kohnen Amanda L. (Amanda Lucille). "Synthesis of 3-aminocyclobutenones via [2 + 2] cycloaddition of ynamides and ketenes." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/73390.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2012.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references.<br>Ynamides react with various classes of ketenes in intermolecular [2 + 2] cycloaddition to afford substituted cyclobutenones with complete regioselectivity. The cycloaddition substrates are easily assembled from amine derivatives by copper-catalyzed N-alkynylation with acetylenic bromides. The alkynylation reaction provides access to thermally sensitive compounds such as diynamides. Synthesis of the requisite halo diynes is achieved by Sonogashira coupling followed by base-mediated elimination at low temperature.<br>by Amanda L. Aguirre Kohnen.<br>S.M.
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Cassú, Ponsatí Daniel. "Rhodium-catalysed [2+2+2] cycloaddition reactions for the preparation of highly functionalised cyclic compounds." Doctoral thesis, Universitat de Girona, 2018. http://hdl.handle.net/10803/565443.
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Transition metal-catalysed [2+2+2] cycloaddition reactions involving unsaturated substrates represent one of the most elegant methods in organic chemistry to prepare functionalised cyclic compound. This doctoral thesis is aimed to achieve a better understanding of the versatility entailed in rhodium-catalysed [2+2+2] cycloadditions and rationalise the associated mechanistic aspects.
After a deep analysis of the bibliographic precedents, which are exposed in the introduction section, and the definition of the objectives for the thesis, the efficiency of several rhodium catalysis in performing the [2+2+2] cycloaddition is evaluated by involving two acetylenes and several C(sp2) unsaturations. On the other hand, the reactivity of linear allene-alkene-alyne substrates is studied both from the experimental and theoretical points of view. Also, the feasibility of using carbon nanotubes is evaluated. Finally, the different conclusions are specified and detailed information related to the experimental methods is given<br>Las reacciones de cicloadición [2+2+2] de sustratos insaturados catalizadas por metales de transición representan uno de los métodos más elegantes en química orgánica para preparar compuestos cíclicos funcionalizados. La presente tesis doctoral pretende lograr un mejor entendimiento sobre la versatilidad de las cicloadiciones [2+2+2] catalizadas por rodio y racionalizar los aspectos mecanísticos asociados.
Tras un profundo análisis de los precedentes bibliográficos, expuestos en la sección de introducción, y la definción de los objetivos planteados para la tesis, se evalúa la eficacia de varios catalizadores de rodio para producir la cicloadición [2+2+2] de dos acetilenos con varias insaturaciones C(sp2). Por otro lado, se estudia de la reactividad de sustratos lineales aleno-alqueno-alquino tanto desde el punto de vista experimental como teórico. Asimismo, también se evalúa la viabilidad de la incorporación de nanotubos de carbono. Finalmente, se especifican las diferentes concluciones extraídas y se detallan los métodos experimentales utilizados
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Kremnev, Jimmy D. "Visible light mediated borylation and [2+2] cycloaddition reactions of Thiazolino Ring Fused 2-Pyridones." Thesis, Umeå universitet, Kemiska institutionen, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-177966.
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Selva, Verónica. "Diastereoselective multicomponent [3+2] and [4+2] cycloadditions." Doctoral thesis, Universidad de Alicante, 2018. http://hdl.handle.net/10045/77573.
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En esta tesis doctoral se ha estudiado los iluros de azometino generados in situ en reacciones de cicloadición 1,3-dipolar y diferentes dipolarófilos para la síntesis multicomponente (libre de metales) de derivados de indolizidina a partir de pipecolinatos, aldehídos y dipolarofilos de forma térmica, y también a partir de ácido pipecólico de forma descarboxilada. También se ha estudiado la reacción de cicloadición 1,3-dipolar térmica multicomponente entre iluros de azometino no activados generados in situ a partir de aminas, aldehídos aromáticos y alquenos electrofílicos para generar derivados de pirrolidina.Además, se describe la síntesis de pirrolizidinas diastereoméricamente enriquecidas a partir de nitroprolinatos enantioméricamente puros a través de una cicloadición 1,3- dipolar multicomponente catalizada por una sal de plata y, por otro lado, una reacción de Amina-Aldehído-Dienófilo (AAD) para sintetizar estructuras ciclohex-2-en-1-ilprolinato como diastereoisómero enantiopuro único de forma multicomponente y libre de metales.
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Lu, Yafan. "(4+3) cycloadditions and tandem (4+3) cycloaddition/nucleophilic trapping reactions of propargylic diether dicobalt complexes via sequential Nicholas reactions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ62246.pdf.
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Cano-Soumillac, Céline. "Synthèse de pharmacophores par cycloaddition [3+2] à partir de carbohydrates." Poitiers, 2004. http://www.theses.fr/2004POIT2287.
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Le travail décrit dans ce manuscrit s'inscrit dans un cadre général de développer une méthodologie propice à la synthèse asymétrique de nouvelles familles de molécules pharmacologiques potentielles. L'étape-clef dans cette approche est la cycloaddition dipolaire-1,3, une réaction avec un fort potentiel, puisque des nouvelles liaisons et des centres asymétriques sont générés en une étape. Aisément accessibles, relativement peu onéreux et possédant de nombreux centres chiraux, les carbohydrates ont été utilisés comme précurseurs de cette réaction. Après une étude bibliographique de la cycloaddition [3+2] appliquée aux sucres, nous décrivons la synthèse régio- et stéréosélective d'isoxazolidines, analogues de la Mésembrine, dans des conditions thermiques classiques puis sous champ micro-ondes. Enfin, dans une seconde partie, nous développons la synthèse de systèmes pyranopyrrolidiniques bicycliques obtenus avec de bons rendements et d'excellentes régio- et stéréosélectivités<br>We describe herein the development of a novel methodology propitious to the asymmetric synthesis of new families of molecules with potential pharmacological interest. Our strategy involves the 1,3-dipolar cycloaddition reaction as key step: indeed, this reaction allows the creation of new bonds and asymmetric centres in a single step. Easily accessible and inexpensive unsaturated sugars are employed as precursors in this reaction, taking advantage of the existing chiral centres. We describe the regio- and stereoselective synthesis of isoxazolidines, a class of molecules of structural analogy with Sceletium alkaloids such Mesembrine. The use of microwaves in the context of the [3+2] cycloaddition reaction using carbohydrates was also explored. The major improvements are reduced time of reaction and higher yields due to reduced side products. Finally, we describe the synthesis of pyranopyrrolidinic bicyclic systems obtained in good yields and high regio- and stereoselectivity
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Saïd, Mohamed Achmet. "La réaction de cycloaddition [3+2] dipolaire assistée par micro-ondes." Poitiers, 2005. http://www.theses.fr/2005POIT2297.
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La réaction de cycloaddition dipolaire [3+2] est un outil puissant pour la préparation de composés hétérocycliques. C'est une méthode facile à mettre en œuvre, tant ses conditions opératoires sont douces, qui nécessite, de plus des réactifs aisément accessibles et peu onéreux. Dans ce manuscrit, nous décrivons l'étude de la réaction de cycloaddition dipolaire à partir d'ylures d'azométhine sous irradiation micro-ondes. L'association de la cycloaddition dipolaire [3+2] avec la chimie des micro-ondes s'est révélée être d'une grande efficacité pour la préparation de plusieurs composés polycycliques en peu d'étapes. Les résultats intéressants obtenus, offrent une nouvelle approche synthétique applicable à la synthèse de nouvelles molécules bioactives. Par conséquent, nous avons préparé un grand nombre de composés potentiellement actifs, de type hydropyrrolique, comme des hydrochroménopyrroles, des hydrobenzoindoles, des hydroindénopyrroles et des oxochroménopyrroles. Ces composés ont pu être préparés dans des temps très courts, avec des rendements généralement très bons<br>The [3+2] dipolar cycloaddition reaction is a powerful tool for the preparation of heterocyclic compounds. It is a facile method, employing straight forward laboratory procedures, and easily accessible reagents. Herein we describe the study of the dipolar cycloaddition reaction from azomethine ylides under microwave conditions. The use of microwaves in this reaction is very efficient for the rapid synthesis of polycyclic compounds. The interesting results obtained permit the development of novel methodology for the synthesis of many molecules with pharmacological potential. As such, we prepared numerous families of compounds such as hydrochromenopyrroles, hydrobenzoindoles, hydroindenopyrroles and oxochromenopyrroles. These compounds were prepared rapidly, generally in very good yields
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Toh, Ophilia Ndi. "Synthesis Towards Fulminic Acid and Its Derivatives in 1, 3-Dipolar Cycloaddition Reactions." Digital Commons @ East Tennessee State University, 2008. https://dc.etsu.edu/etd/1982.
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A new approach to fulminic acid cycloadditions has been developed. At reduced temperatures, fulminic acid is generated in situ and undergoes 1, 3-diploar cycloaddition reactions with dipolarophiles to form isoxazolines and/or its dimers. This procedure represents a novel, safe general method for the one-step generation of fulminic acid, which complements existing potentially explosive protocols.
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Lam, Yan-yu Sarah, and 林恩如. "Studies and applications of intermolecular (4+3) cycloaddition reactions of epoxy and aziridinyl enolsilanes." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/206359.
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Bala, Kason. "1, 3-dipolar cycloaddition reactions in aqueous media and investigations into solid phase ether synthesis." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397163.
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Picard, Sébastien. "Etude de la synthèse d'alcaloïdes indoliques par réaction de cycloaddition [3+2] intramoléculaire." Poitiers, 2007. http://www.theses.fr/2007POIT2317.
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Eroksuz, Serap. "A New P-fam-silver Catalyst For Asymmetric 1,3-dipolar Cycloaddition Reactions Of Azomethine Ylides." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609801/index.pdf.
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In this study new twelve phosphorus based chiral ligands were synthesized and characterized. Then the catalytic activity of these chiral ligands was tested with Cu(II) and Ag(I) salts in asymmetric 1,3-dipolar cycloaddition reactions of azomethine ylides. This method provides the synthesis of different pyrrolidine derivatives with up to four stereogenic centers. Pyrrolidine derivatives are found in the structure of many biologically active natural compounds and drugs. Therefore the asymmetric synthesis of these compounds is highly important and many groups are involved in this area. As the precursor of the azomethine ylides, N-benzyliden-glycinmethylester, N-(4-methoxy benzyliden)-glycinmethylester, N-(naphthalene-1-ylmethylene)-amino-acetic acid methyl ester, and N-(naphthalen-2-ylmethylene)-amino-acetic acid methyl ester were synthesized and used. As the dipolarophiles, methyl acrylate, dimethyl maleate and N-methyl maleimide were used. Using these imines and dipolarophiles with 6 mol % of one of the P-FAM chiral ligands in the presence of Ag(I) salt, pyrrolidine derivatives were synthesized in up to 95% yield and 89% enantioselectivity. Additionally, chiral ligand was recovered in more than 80% yield and reused without losing its activity.
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Black, Elzie Dewayne. "An investigation of a novel phase transfer system - the Omega Phase : the synthesis and [4&2] cycloaddition reactions of chiral 2-phenylpropanthial." Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/27308.
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Melgar, Gliseida Zelayaran. "Estudos visando a sintese de derivados do acido 4-amino-3- (4clorofenil) butirico (BACLOFEN)." [s.n.], 2000. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250235.
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Previous issue date: 2000<br>Resumo: O ácido g-aminobutírico (GABA) é o mais importante neurotransmissor inibitório presente no Sistema Nervoso Central. Ele sozinho é responsável por 34% de todas as sinapses que ocorrem no cérebro. A ação do GABA no SNC é realizada através da interação com dois tipos diferentes de receptores, classificados por Hill e Bowery como GABAA e GABAB. Esses receptores apresentam diferentes propriedades de ligação e, conduzem quando ativados, a efeitos biológicos diferentes. O ácido 4-amino-3(R)-4-clorofenilbutírico (baclofen) é um agonista seletivo para o receptor GABAB, que apresenta um certo grau de lipofilicidade, podendo com isso atravessar a barreira hematoencefálica. A necessidade de se desenvolver substâncias que podem atuar como antagonistas seletivos levou ao desenvolvimento do faclofen, do saclofen e do hidroxisaclofen. Nesse trabalho avaliamos a utilização de duas estratégias sintéticas numa nova abordagem para a preparação de derivados conhecidos e não conhecidos do Baclofen. Exploramos inicialmente uma estratégia já conhecida em nosso laboratório, que se baseava no emprego de uma a,a'-diclorociclobutanona, obtida através de uma reação de ciclo adição [2+2]. Essa última foi transformada na lactona 7. Várias tentativas de abertura dessa lactona foram realizadas, conduzindo a g-dicloroéster 1, o álcool éster sililado 9, o diol 11 e o g-iodoéster 15. De todas as tentativas, aquela que forneceu o intermediario 15 foi a de melhor rendimento. Esse último pode ser transformado no amino álcool 18, importante intermediário para a síntese de homólogos do Baclofen. Além disso, avaliamos também o aduto de Baylis-Hillman 19, como matéria prima para a preparação de derivados do Baclofen. Esse foi reduzido quimiosseletivamente para fornecer o diol 28. Proteção desse diol forneceu o cetal 36, que teve a dupla ligação submetida a uma reação de clivagem oxidativa com OsO4/NaIO4 para fornecer a acetona 37 com 78% de rendimento. A adição de um reagente organolítio derivado do 4-bromoclorobenzeno sobre a carbonila de 37 forneceu o intermediário para a síntese dos derivados hidroxilados do Baclofen. Essa segunda abordagem nos permitiu estabelecer uma nova aproximação à síntese total de derivados do Baclofen, uma importante classe de compostos terapêuticos<br>Abstract: The g-aminobutiric acid (GABA) is the most important inhibitory neurotransmitter present in the mammalian central nervous system (CNS). This acid is responsable for 30% of all the synapses occuring in the human brain. The action of GABA in the SNC is carried out through the interaction with two different types of receptors, classified by Hill and Bowery as GABAA and GABAB. These receptors present different binding properties, which led to different biological effect when activated. There are in the literature several examples of substances acting on GABAA receptor, however there are only few examples acting on GABAB. The 3-(R)-4-amino-3-(4chlorophenyl)butanoic acid or Baclofen is the only therapeutically available GABAB agonist known. This compound is used on the treatment of spasticity, a serious disease characterized by an increase muscle tone usually perceived as muscle tightness or achiness in the limbs and associated normally with multiple sclerosis (MS). Besides Baclofen there are others known substances acting on GABAB receptors as antagonist. In this class we can notice phaclophen, saclophen and hydroxysaclophen. In this work we describe our results concerning the exploitation of two strategies aiming to the preparation of intermediates to the synthesis of Baclofen derivatives. Initially we have explored a strategy will documented in our laboratory, based on the [2+2] cycloaddition reaction the a,a'-dichlorocyclobutanone, obtained from the cycloaddition was transformed in the lactone 7, by ring expansion. The opening of the lactone was very troublesome and led to the g-dicloroester 1, the silylated alcohol ester 9, the diol 11 and the g-iodoester 15. The g-iodoester 15 easily obtained from 7 by treatment with TMSI was transformed into the amino alcohol 18, an important intermediate for the synthesis of Baclofen homologue series.We have also evaluated the potentiality of the Baylis-Hillman adduct 19, as starting material for the synthesis of Baclofen derivatives. The Baylis-Hillman adduct was chemoselectivily reduced to provide the diol 28, which was transformed to the ketal 36. The exocyclic double bond of 36 was transformed to ketone 37 in 78% yield, by oxidative cleavage with OsO4/NaIO4 The addition of the organolithium reagent derived of 4-bromoclorobenzene on the carbonyl of 37 led to the isomers 40 and 42. These intermediates can be used to the synthesis of hidroxylated derivatives of the Baclofen and the Baclofen itself. This second strategy has permitted to us establish a new approach to the total synthesis of Baclofen derived of this important class of therapeutically useful compounds<br>Mestrado<br>Quimica Organica<br>Mestre em Química
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Leftwich, Timothy Ray. "Modification of silicon-based substrates with cyclocondensation and cycloaddition reactions." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 111 p, 2010. http://proquest.umi.com/pqdweb?did=1992491831&sid=7&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Ranasinghe, Gamage Indeewari. "New Reactivity Involving N-Isothiocyanates: Aminothiocarbonylation and [3+2] Cycloadditions to Form Molecules Containing NNCS Motifs." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36042.
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Nitrogen-containing heterocycles are of vital importance for the pharmaceutical and agrochemical industries. The Beauchemin group has been studying rare, amphoteric nitrogen-substituted isocyanates over the past years, and showed that their [3+2] alkene cycloaddition and cascade reactions provide access to a variety of NNCO containing heterocyclic compounds. This triggered interest into the reactivity of the parent N-isothiocyanates, which are also rare, and led to the discovery of aminothiocarbonylation reactions. The products formed are azomethine imines which contain a cyclic -aminothiocarbonyl motif, thus providing a cycloaddition route to these useful dipoles from simple starting materials. Such aminothiocarbonylation reactions were developed with both alkenes and imines as substrates.Apart from cyclic azomethine imine formations, efforts have also been made toward forming the acyclic azomethine imines as intermediates. These intermediates undergo [3+2] cycloaddition to form thiocarbamoyl pyrazolidine derivatives, and a preliminary substrate scope for this new intermolecular reactivity is presented. Other preliminary results include an unexpected Chugaev type reactivity. Collectively, these results show that N-isothiocyanates hold significant potential for the development of new reactivity.
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Liu, Yang. "Studies on Palladium-Catalyzed [3+2]-Annulation/Domino Reactions." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS214.
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Ce travail de thèse est consacré à l'étude des réactions d'annélation [3+2] domino catalysées au palladium. Tout d'abord, une nouvelle séquence domino a été développée, qui implique la réaction entre les dérivés cycliques α,β-insaturés-γ-oxy-carbonylés et les acétamides stabilisés par résonance. Les pyrrolidine-2-ones bicycliques obtenues ont été générées par une allylation intermoléculaire catalysée au Pd, suivie d'une réaction d’aza-Michael intramoléculaire. Une version asymétrique a également été réalisée, obtenant jusqu'à 60% d’excès énantiomérique. Ensuite, une nouvelle séquence domino triple catalysée au Pd [allylation / aza-Michael / keto α-arylation] (ALAMAR) a également été réalisée, ce qui permet la formation sélective de systèmes tricycliques fusionnés en un seul pot. Enfin, deux transformations domino sélectives et complémentaires ont été réalisées, permettant d'effectuer au choix des annulations de type C−C/O−C ou C−C/C−C [3+2]. Ces transformations se produisent par le biais d'une séquence de [C-allylation intermoléculaire / O- ou C-1,4-addition conjuguée intramoléculaire]<br>This thesis work is consecrated to the study of palladium-catalyzed [3+2]-annulation and domino reactions. First, a new domino sequence was developed, which involves the reaction between cyclic α,β-unsaturated-γ-oxy-carbonyl derivatives and resonance-stabilized acetamides. The resulting bicyclic pyrrolidin-2-ones were generated through an intermolecular Pd-catalyzed allylation followed by an intramolecular aza-Michael reaction sequence. An asymmetric version was also achieved, obtaining up to 60% ee. A new Pd-catalyzed [allylation / aza-Michael / keto α-arylation] (ALAMAR) triple domino sequence was also accomplished, which allows the selective one-pot formation of fused tricyclic systems. Lastly, two selective and complementary domino transformations have been achieved, which allow to perform C−C/O−C or C−C/C−C [3+2]-annulations at will. These transformations occur through an intermolecular Pd-catalyzed C-allylation / intramolecular O- or C-1,4-addition sequence, respectively
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Martin, Yvonne. "Pseudodistomin E Versuche zur Totalsynthese über das Konzept der Tandem-Wittig-[3+2]-Cycloaddition /." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982931980.
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Fihi, Rachid. "Synthese et evolution de spiroheterocycles obtenus par cycloaddition 3+2 sur quelques methylene lactones." Besançon, 1994. http://www.theses.fr/1994BESA2052.
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La premiere partie de la these est consacree a la preparation de lactones et lactames a double liaison methylenique juxtacyclique pouvant etre eventuellement benzocondenses et de precurseurs de dipole-1,3. La synthese de plusieurs composes bi et tricycliques a jonction spiranique est decrite en seconde partie. Elle fait appel essentiellement a la reaction de cycloaddition dipolaire-1,3 qui est totalement regioselective. Les structures ont ete attribuees sans ambiguite sur la base des spectres de rmn #1h et #1#3c. Lorsque le probleme se pose, l'etude de la stereoselectivite a ete abordee. Les diastereoisomeres sont alors separes et leur configuration attribuee grace a la rmn. La deuxieme partie est consacree a l'etude des reactions de rearrangements des spiroheterocycles obtenus precedemment, soit sous l'action de la chaleur, soit en presence d'acides mineraux. Ainsi le bis-adduit, obtenu par cycloaddition des arylnitriloxydes avec la protoanemonine dans le toluene a reflux, conduit via une double cycloaddition suivie d'une perte de co#2 a une bis-isoxazoline, caracterisee par spectroscopie de masse et par une structure radiocristallographique. En milieu acide tous les autres adduits, sauf ceux qui derivent des -methylene lactones, conduisent a des acides carboxyliques par ouverture du cycle lactonique et aromatisation du cycle oxazoline. Certains monoadduits permettent enfin d'acceder par rearrangement a des analogues heterocycliques de l'acide trans-cinnamique
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Decuypère, Elodie. "Etude de réactions de cycloaddition [3+2] impliquant des composés mésoioniques et des dipolarophiles." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS395.
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Le premier objectif de ce travail a consisté à développer la réaction CuSAC (découverte au laboratoire) pour la synthèse régiosélective de pyrazoles poly-substitués, dans un contexte de méthodologie de synthèse. Il existe de nombreux composés biologiquement actifs contenant le motif pyrazole et peu de méthodes régiosélectives décrites pour les synthétiser. Développer une nouvelle réaction pour obtenir des pyrazoles poly-substitués de façon contrôlée était donc très intéressant pour des applications synthétiques.Le deuxième objectif a été d’appliquer cette réaction à la bioconjugaison et notamment au développement de sondes profluorescentes Des coumarines-sydnones subissant un effet d’extinction de fluorescence par le phénomène PeT ont été développées. Suite au couplage avec un alcyne, le pyrazole formé n’éteint plus lafluorescence de la coumarine. Ce type de sondes est très intéressant pour le marquage de biomolécules, car il n’y a aucun parasitage de fluorescence et donc ne nécessite aucun lavage.Le troisième objectif de la thèse a été d’explorer la réactivité des composés mésoioniques pour un alcyne, sous une catalyse au cuivre, dans le but de découvrir de nouvelles réactions click. Un criblage de 24 composés dans 9 conditions de catalyses différentes, faisant plus de 200 réactions réalisées, a été effectué. Deux réactions ont été révélées, dont une très prometteuse. Celle-ci permet dans la même opération de lier deux partenaires tout en libérant un fragment d’un des deux partenaires. Cette réaction a été étudiée dans le but de développer un outil de théranostique où être utilisée pour la mise au point de nouveaux espaceurs clivables<br>The first aim of this work was the development of a new regioselective synthetic access to poly-substituted pyrazoles via the CuSAC reaction, previously discovered in the laboratory. The development of new reactions leading to poly-substituted pyrazoles with a full control of regioselectivity is highly interesting for synthetic applications.The second aim of this work was the application of this reaction for the labeling of complex biomolecules. To broaden the scope of the CuSAC, fluorogenic coumarin-sydnones which undergo fluorescence extinction via PeT have been designed and synthetized. Following the coupling reaction, the newly formed pyrazole core allows huge enhancement of the fluorescence signal.This kind of probes is highly interesting in the specific labelling of biomolecules avoiding washing steps.The last project of this thesis have been focused on the discovery of new [3+2] cycloaddition reaction implying a mesoionic compound and a terminal alkyne under copper catalysis. 24 mesoionic dipoles were screened for their ability to react with a terminal alkyne in 9 different catalytic conditions, yielding to more than 200 reactions screened. Two hits were identified, one of them holding great promise. This hit allows an efficient “click and release” reaction which should find tremendous applications, especially in the fields of theranostic and cleavable linker development