Les motifs de type pyridine sont des motifs centraux dans de nombreux domaines, aussi bien rencontrés dans divers principes actifs en chimie médicinale, qu’en agrochimie, chimie des matériaux et des polymères, et enfin en synthèse organique de manière générale. De nombreuses voies d'accès toujours plus simples et directes à des motifs de type pyridine polysubstituées ont été proposées dans la littérature, et, parmi ceux-ci, le motif de type aminopyridine fusionnée à retenu notre attention. En effet peu de rapports d'un tel motif sont fait dans la littérature, en partie en raison du défi synthétique que représente ce squelette. Une méthode convergente en trois étapes clefs permettant d'accéder à une large gamme d'aminopyridines fusionnées est décrite dans ce manuscrit, ainsi que son extension par chimie en flux continu permettant une synthèse multi-grammes de ces composés. Enfin une étude théorique du mécanisme est proposée afin d'élucider l'influence des différents paramètres de la réaction. / Pyridine scaffolds are very interesting building blocks in various fields, they appear in various drugs, and are relevant either in agrochemistry, marials chemistry, polymers and in organic chemistry. Many efficient and direct methods to access polysubstituted pyridine scaffolds are described in the litterature, amongst these, the fused aminopyridines caught our attention. Indeed, there are only few reports in the litterature of such scaffold.

The advent of transition metal catalysis has greatly expanded the scope of viable cycloaddition reactions, allowing for the direct synthesis of highly functionalized and complex biologically active compounds. By manipulating various aspects of catalyst structure, including the supporting ligands and the central metal, the function of a catalyst can be modified. In this context, the catalytic properties of dinuclear complexes have not been greatly explored in cycloaddition reactions. Our research has focused on studying the catalytic properties of dinuclear complexes in cycloaddition reactions. Comparative studies between dinuclear and mononuclear Ni-complexes led us to discover and develop an efficient route to synthesize 1,2,4-trisubstituted benzene derivatives from terminal alkynes. The key organometallic intermediates in this process were isolated, and computational studies were performed to unravel a novel bimetallic mechanism for alkyne cyclotrimerizations. As an extension of this study, we have found that the dinuclear catalyst is capable of catalyzing the methylenecyclopropanation of olefins. The reaction uses 1,1-dichloroalkene as a vinylidene precursor along with Zn as a stoichiometric reductant. A wide range of monosubstituted terminal alkenes and relatively unhindered internal alkenes are viable substrates. Furthermore, to understand the mechanism of vinylidene transfer, various stoichiometric and stereochemical experiments were performed. Furthermore, we discovered that mononuclear and dinuclear Ni-complexes are highly efficient in achieving vinylidene insertions into Si–H bonds to synthesize Si-containing heterocyclic molecules. Ongoing efforts are directed toward optimizing the reaction conditions and elucidating the substrate scope of the reaction.

In the context of ongoing efforts toward C-aryl glycoside synthesis, a recently developed approach to form C-aryl glycals from 2-deoxysugar lactones was expanded to form novel substrates. This approach has been applied to the synthesis of various furyl glycals, allowing access to C-aryl glycals via a benzyne furan (4+2) cycloaddition methodology. The hydroboration-oxidation of said C-aryl glycals has allowed access to C(2)-oxygenated C-aryl glycosides via the benzyne cycloaddition approach. An approach to the total synthesis of 5-hydoxyaloin A is detailed, in which regioselective benzyne furan (4+2) cycloadditions were achieved via the use of a silicon tether. Two approaches to the anthrone core have been applied; one in which an unsymmetrically-substituted aryl ring is first constructed by means of a silicon tether, and one in which the unsymmetrically-substituted ring is formed last, also utilizing a silicon tether. The latter approach has allowed access to the anthrone core of 5-hydroxyaloin A, and only a final desulfurization remains in order to access the natural product. / text