Imidoyl sulfoxonium ylides as new precursors of a-imino metal-carbene complexes in organic synthesis

Abstract

In recent years, sulfur ylides have received significant attention as equivalents of diazo compounds and as precursors of metal-carbene complexes. Although significative advances have been made regarding the use of a-carbonyl metal-carbenes as intermediates in organic synthesis, a less explored type of metal-carbene, containing a-imino group, still have limited sources and few general applications. In this context, our research group envisioned the possibility of using imidoyl sulfoxonium ylides as potential precursors to generate a-imino metal-carbene intermediates. To support our proposal, we recently reported a direct intramolecular C-H functionalization of imidoyl sulfoxonium ylides in the presence of iridium catalyst to provide 2-substituted indoles in a single step. Now, we intend to explore even more the versatility of imidoyl sulfoxonium ylides in classical metal-carbene-mediated transformations to provide functionalized imino products and structural-diverse heterocycles.To this purpose, it is necessary to extend the existing methods in order to achieve other imidoyl sulfoxonium ylides such as the N-alkyl substituted and a-aryl-b-imidoyl substituted ylides. The research group of professor Christophe Aïssa has developed a general protocol for palladium-catalyzed cross-coupling reaction between sulfoxonium ylides and (hetero)aryl bromides or triflates, providing a broader scope of a-aryl-b-carbonyl-sulfoxonium ylides. We intend to use the experience of Prof. Aïssa to achieve a-aryl-b-imidoyl sulfoxonium ylides and apply these new substrates in X-H insertion, C-H functionalization and heretoannulations reactions. (AU)