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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Etude de la réaction d’esters ω-insaturés médiée par l’iode hypervalent et catalysée par le cuivre : développement d’une nouvelle réaction d’aminolactonisation. Application à la synthèse d’hétérocycles originaux fonctionnalisés / Copper-catalyzed iminoiodane-mediated aziridination of omega-unsaturated esters : development of a new aminolactonization reaction. Application to the synthesis of fonctionnalized heterocycles

Karila, Delphine 08 November 2011 (has links)
La réaction d’aziridination catalysée par les sels de cuivre permet de former des aziridines à partir d’oléfines en employant une source de nitrènes générée à partir de aryliminoiodanes.Le développement au laboratoire d’une version « one-pot » impliquant l’iodosylbenzène et un sulfonamide ainsi que l’emploi de l’iminoiodane N-Ses a rendu cette réaction plus attractive en synthèse.La première partie de ce travail a été consacrée à l’étude de la réactivité particulière des esters ω-insaturés dans les conditions d’aziridination. En effet, dans ces conditions, l’aziridine subit une ouverture intramoléculaire par le carbonyle de l’ester pour fournir une γ-lactone 5,5-disubstituée. Cette nouvelle réaction, baptisée réaction d’aminolactonisation, a été exemplifiée sur une série de dérivés styréniques 1-propanoates ou butanoates pour donner les γ-lactones correspondantes avec de très bons rendements. Cependant, sans doute pour des raisons stériques, les composés o-bromés et o-chlorés ont donné majoritairement le produit d’aziridination sans évoluer vers la forme lactonique. Par la suite, ces aziridines placées en milieu acide, ont conduit à la formation de γ-lactones ortho halogénées avec de bons rendements. Enfin, le champ d’application de cette méthodologie a été étendu à la formation d’hétérocycles gem-disubstitués, au départ d’alcools oléfiniques et de carbamates insaturés.La seconde partie de ce travail a été consacrée à l’élaboration d’hétérocycles fonctionnalisés à partir des produits issus de la réaction d’aminolactonisation. Ainsi, en exploitant la réactivité de la partie aromatique, il nous a été possible, notamment via des réactions de couplage croisé, d’obtenir différents motifs tels que des spiroindolines, des indolines gem-3,3-disubstituées ou encore des indolinobutyrolactones avec de très bons rendements. Par ailleurs, en usant de la réactivité de certaines γ-lactones, il nous a été possible d’élaborer deux autres motifs relativement intéressants tels qu’une benzospirolactone ou encore un spirohexahydropyrroloindole. Ce dernier composé a fait l’objet d’une étude approfondie dans le cadre de la synthèse d’un analogue spirolactone de la physostigmine, molécule utilisée notamment dans le traitement de la maladie d’Alzheimer.Enfin, dans le cadre d’une approche à la synthèse de la Fiscaline A, possédant un motif indoline 3,3-disubstituée au sein de sa structure, nos efforts se sont concentrés sur la fonctionnalisation de la position C-2 du noyau indoline. L’ensemble des stratégies élaborées a fait l’objet de la troisième partie de ce travail de thèse. / The reaction of an olefin with a nitrene generated from a phenyliminoiodane in the presence of a copper catalyst allows the direct formation of an aziridine.The versatility of this reaction was improved by a one-pot procedure developed in our laboratory mediated by iodosylbenzene and a sulfonamide and by the use of Ses iminoiodane. The first part of this thesis was devoted to the study of the unexpected reaction observed with ω-unsaturated esters under aziridination conditions in which an intramolecular ring-opening of the aziridine by the carbonyl oxygen of the ester function is observed providing a 5,5-disubstituted butyrolactone. This new reaction named aminolactonization reaction has been used on various styrene-derived 1-propanoates or butanoates for the synthesis of 5,5-disubstituted butyrolactones in high yields. Probably due to hindrance effects, o-bromo and o-chloro compounds selectively gave the aziridination product. The reactivity of these compounds, under acidic conditions, has been investigated and various ortho halogenated γ-lactones have been obtained in good yields. Finally, the field of application of this methodology has been extended to the formation of gem-disubstituted heterocycles starting from, for example, an olefinic alcohol and an unsaturated carbamate. The second part of this work was dedicated to the elaboration of functionalized heterocycles starting from aminolactonization products. To this end, the reactivity of the aromatic ring has been studied to give access to new scaffolds such as spiroindolines, gem-3,3-disubstituted indolines and indolinobutyrolactones in good yields. Furthermore, the reactivity of such γ-lactones allowed us to synthesize new interesting scaffolds such as benzospirolactone or spirohexahydropyrroloindole. The latter has been used as an intermediate for the synthesis of a spirolactone analogue of physostigmine used for the treatment of Alzheimer’s disease.Finally, this methodology was further exploited for an approach to the total synthesis of Fiscalin A, focusing on the C-2 functionalization of the indoline ring. The results are discussed in the third part of this work.
2

Catálise oxidativa de clusters de rutênio e porfirinas supramoleculares / Oxidative catalysis of ruthenium clusters and supramolecular porphyrins

Nunes, Genebaldo Sales 11 July 2005 (has links)
A atividade catalítica de clusters trigonais de acetato de rutênio e porfirinas supramoleculares contendo quatro unidades de clusters periféricos ou complexos de bis(bipiridina)rutênio, na oxidação de substratos orgânicos por iodosil-benzeno ou terc-butil-hidroperóxido, é abordada nesta tese. Foram feitos estudos cinéticos para elucidar o mecanismo de catálise, com especial destaque para duas espécies supramoleculares isoméricas representadas por Mn(3-TRPyP) ou Mn(4-TRPyP), nos quais os complexos de bis(bipiridina)(cloro)rutênio se coordenam à tetrapiridilporfirina através das posições meta ou para da ponte piridínica, respectivamente. Além da maior seletividade proporcionada pelos catalisadores supramoleculares, a substituição do íon cloreto pela água nos complexos periféricos de rutênio, intensificou a atividade catalítica, gerando novos sítios ativos, do tipo Ru(IV)=O. Também foram estudados clusters trinucleares de rutênio, altamente reativos, no estado Ru(III)Ru(IV)Ru(IV)=O. Estes foram gerados eletroquimicamente em solução aquosa, apresentando pronunciada atividade catalítica na oxidação do alcool benzílico. Finalmente, uma espécie dimérica de cluster, ainda inédita, com ponte oxo, foi caracterizada e investigada do ponto de vista catalítico. / The catalytic activity of trinuclear ruthenium clusters and supramolecular tetrapyridylporphyrins containing four peripheral cluster units or bis(bipyridine)ruthenium complexes, in the oxidation of organic substrates by iodosylbenzene or tert-butil-hydroperoxide, is dealt with in this thesis. Kinetic studies were performed in order to elucidate the mechanisms of catalysis involving two isomeric species denoted Mn(3-TRPyP) or Mn(4-TRPyP), in which the bis(bipyridine)(chloro)ruthenium complexes are bound to the tetrapyridylporphyrin center, at the meta or para positions of the pyridine bridge, respectively. In addition to the improved selectivity by such supramolecular catalysts, the substitution of the chloride ion by water in the peripheral ruthenium complexes, greatly enhanced their catalytic activity by generating new Ru(IV)=O reactive sites. Highly reactive trinuclear ruthenium clusters of the type Ru(III)Ru(IV)Ru(IV)=O were also generated electrochemically in aqueous solution, exhibiting pronounced catalytic activity in the oxidation of benzyl alcohol. Finally, a novel dimeric oxo-bridged cluster species was characterized, and its role in catalysis investigated.
3

Catálise oxidativa de clusters de rutênio e porfirinas supramoleculares / Oxidative catalysis of ruthenium clusters and supramolecular porphyrins

Genebaldo Sales Nunes 11 July 2005 (has links)
A atividade catalítica de clusters trigonais de acetato de rutênio e porfirinas supramoleculares contendo quatro unidades de clusters periféricos ou complexos de bis(bipiridina)rutênio, na oxidação de substratos orgânicos por iodosil-benzeno ou terc-butil-hidroperóxido, é abordada nesta tese. Foram feitos estudos cinéticos para elucidar o mecanismo de catálise, com especial destaque para duas espécies supramoleculares isoméricas representadas por Mn(3-TRPyP) ou Mn(4-TRPyP), nos quais os complexos de bis(bipiridina)(cloro)rutênio se coordenam à tetrapiridilporfirina através das posições meta ou para da ponte piridínica, respectivamente. Além da maior seletividade proporcionada pelos catalisadores supramoleculares, a substituição do íon cloreto pela água nos complexos periféricos de rutênio, intensificou a atividade catalítica, gerando novos sítios ativos, do tipo Ru(IV)=O. Também foram estudados clusters trinucleares de rutênio, altamente reativos, no estado Ru(III)Ru(IV)Ru(IV)=O. Estes foram gerados eletroquimicamente em solução aquosa, apresentando pronunciada atividade catalítica na oxidação do alcool benzílico. Finalmente, uma espécie dimérica de cluster, ainda inédita, com ponte oxo, foi caracterizada e investigada do ponto de vista catalítico. / The catalytic activity of trinuclear ruthenium clusters and supramolecular tetrapyridylporphyrins containing four peripheral cluster units or bis(bipyridine)ruthenium complexes, in the oxidation of organic substrates by iodosylbenzene or tert-butil-hydroperoxide, is dealt with in this thesis. Kinetic studies were performed in order to elucidate the mechanisms of catalysis involving two isomeric species denoted Mn(3-TRPyP) or Mn(4-TRPyP), in which the bis(bipyridine)(chloro)ruthenium complexes are bound to the tetrapyridylporphyrin center, at the meta or para positions of the pyridine bridge, respectively. In addition to the improved selectivity by such supramolecular catalysts, the substitution of the chloride ion by water in the peripheral ruthenium complexes, greatly enhanced their catalytic activity by generating new Ru(IV)=O reactive sites. Highly reactive trinuclear ruthenium clusters of the type Ru(III)Ru(IV)Ru(IV)=O were also generated electrochemically in aqueous solution, exhibiting pronounced catalytic activity in the oxidation of benzyl alcohol. Finally, a novel dimeric oxo-bridged cluster species was characterized, and its role in catalysis investigated.

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