Synthesis of pro-chiral beta-ketosulfoxonium ylides and its applications in asymmetric gold-catalysed insertion reactions

Abstract

The insertion of atoms such as C, N, O and S in organic compounds catalyzed by metals has been reported as a mild and efficient method for the synthesis of a broad class of important functionalized structures. In particular, diazocompounds have been applied as precursors for metal carbenes and used in a number of strategies for the intra and intermolecular insertion reactions. Although the use of transition metal carbenes from diazo compounds constitute a powerful tool in organic synthesis, and several metals have been reported to mediate this transformation effectively, there is a gap as regard to the enantioselective reactions. Additionally, there is a need to develop reagents to substitute diazocarbonyl compounds, precursors of the metal carbenes of interest. Recently, a great interest in the development and application of gold catalysts in different reactions has appeared, including the catalytic decomposition of diazocompounds and their insertion into X-H bonds, where X can be C, S, O, N or Si. Considering the importance of stereocontrolled alfa-heterofunctionalization reactions applying metal carbenes, the need to develop versatile precursors for synthesis of these carbenes and the recent interest in gold-catalyzed reactions, we propose in this project: the synthesis of prochiral beta-ketosulfoxonium ylides in an new way and their use in the formation of chiral gold carbenes. The same will be employed in insertion reactions and asymmetric cyclopropanation, as well as reactions of cyclization and ring expansion.