For the past years, our laboratory has been interested in the development of a specific class of functionalised orthoester derivatives and their application as annelating reagents. Previous work had demonstrated that these reagents could be used in a two-step procedure to generate interesting spirocyclic ketones. At the onset of our thesis, we devoted our efforts to the study and application of this methodology. This resulted in an improved and more efficient procedure for the spirohexannelation of â-ketoketals. During these initial studies, an intriguing and novel transannular cyclisation was discovered. The reactivity of these spirocycles was also briefly examined, laying the ground for an application to the total synthesis of Agarospirol, Hinesol and á-Vetispirene, three natural products belonging to the Spirovetivane family. The applicability of a CAN-catalysed deprotection of ketals and silyl ethers, in the presence of an enol triflate moiety, was also investigated. The potential of our functionalised orthoesters as annelating agents was then further evaluated in the context of other silyl enolethers. The heteroaromatic derivatives of furan proved to be excellent coupling partners for our functionalised orthoesters, and enabled the efficient preparation of a wide array of butenolides. These butenolides could then be elaborated, by an efficient and highly stereoselective radical-mediated cyclisation, into bicyclic lactones. Alternatively, treatment with base triggered an efficient spirocyclisation, delivering spirocyclic butenolides in good to excellent yields. The corresponding pyrrole derivative was also examinated, and preliminary work hints at the possibility of readily preparing azaspirocycles as well as indolizidine frameworks. Finally, the evaluation of silylated acyloins allowed an entry into the chemistry of cyclobutanones, and a simple procedure for the synthesis of spirocyclic ethers was developed. During these investigations, an unexpected fragmentation was serendipitously discovered upon application of the Beckmann rearrangement. We were able to use this reaction in a new procedure for the synthesis of interestingly substituted tetrahydropyrans.

Une large série d’imidazo[4,5-b]porphyrines a été synthétisée par condensation acido catalysée du 2,3-dioxo-5,10,15,20-tétraarylchlorines avec des aldéhydes aromatiques. Les propriétés stériques et électroniques des substituants méso-aryle sur le macrocycle tétrapyrrolique ont une influence importante sur le rendement en produit qui peut varier de 18% à 90%. L'analyse par diffraction des rayons X de la structure cristalline du 5,10,15,20-tétramésityl-2-(4-pyridyl)-1H-imidazo[4,5-b]porphyrinate de zinc(II) a montré qu'à l'état solide ce complexe forme des polymères de coordination. Ensuite, différentes méthodes de greffage des imidazoporphyrines sur la surface de TiO2 et ZrO2 mésoporeux ont été étudiées pour évaluer l'intérêt de ces matériaux hybrides en catalyse. La photo-oxydation en milieu homogène des sulfures en sulfoxydes par l'oxygène de l'air en présence de 5,10,15,20-tétramésityl-2-(4-diéthoxyphosphorylphényl)-1H-imidazo[4,5-b]porphyrinate d'indium(III) a été mis en œuvre. Il a été ainsi montré que le complexe supporté par le TiO2 pouvait être recyclé plusieurs fois malgré un lessivage partiel (1%) du catalyseur en solution. Puis, le 5,10,15,20-tétramésityl-2-(4-diéthoxyphosphorylphényl)-1H-imidazo[4,5-b]porphyrinate de manganèse(III) supportée par TiO2 a été utilisé comme catalyseur pour l'oxydation de sulfures en sulfoxydes par l'oxygène moléculaire en présence d'isobutyraldéhyde. Une large série de sulfoxydes a été préparée avec des rendements élevés (> 89%). Le catalyseur a été recyclé 7 fois sans perte de son efficacité et de sa sélectivité. Dans les conditions mises en jeu le lessivage du catalyseur en solution n'a pas été observé. / A broad series of functionalized imidazo[4,5-b]porphyrins was synthesized by the acid-catalyzed condensation of 2,3-dioxo-5,10,15,20-tetraarylchlorins with aromatic aldehydes. Both steric and electronic features of meso-aryl substituents influence on the product yield ranging from 18% to 90%.Single-crystal X-ray diffraction analysis of the structure of zinc(II) 5,10,15,20-tetramesityl-2-(4-pyridyl)-1H-imidazo[4,5-b]porphyrinate showed that this compound forms 1D coordination chains in the solid state.The post-synthetic modifications of imidazo[4,5-b]porphyrins were investigated by performing the Suzuki-Miyaura coupling reaction, preparing water-soluble imidazoporphyrins and linear/angular bis(imidazo)porphyrins.Several methods of grafting of imidazoporphyrins on the surface of mesoporous TiO2 and ZrO2 were investigated to prepare hybrid materials for catalysis.Then, it was demonstrated that indium(III) 5,10,15,20-tetramesityl-2-(4-diethoxyphospho-rylphenyl)-1H-imidazo[4,5-b]porphyrinate catalyzes the photooxidation of sulfides to sulfoxides by oxygen from air. This complex grafted on TiO2 surface was efficient as a reusable catalyst in spite of partial (1%) leaching of imidazoporphyrin in solution. TiO2-supported manganese(III) 5,10,15,20-tetramesityl-2-(4-diethoxyphosphoryl-phenyl)-1H-imidazo[4,5-b]porphyrinate was employed for catalytic oxidation of a broad range of sulfides by pure oxygen in the presence of isobutyraldehyde. All sulfoxides were obtained in high yields (>89%). The catalyst was reused in 7 consecutive cycles without loss of its efficiency and selectivity. Leaching of the catalyst was not observed under studied conditions.