Asymmetric Allylation by Chiral Organocatalyst‐Promoted Formal Hetero‐Ene Reactions of Alkylgold Intermediates

Abstract

An unprecedented catalytic asymmetric allylation of isatins and isatin-derived ketimines is reported enabled by agold and chiral organocatalyst cooperative catalysis strategy. This method offers expeditious access to chiral 2,5-disubsituted alkylideneoxazolines containing vicinal stereogenic centers, mainly in optically pure form, and which are otherwise impossible to access.Mechanistic evidence reveals the presence of an alkylgold intermediate,and an X-raycrystal structure of the allylgold species illuminates its unique stability and reactivity.A na symmetric formal hetero-ene reaction of this gold intermediate,i nvolving ad earomatization process,i s enabled with assistance of aq uinine-derived squaramide catalyst. This novel discovery extends the synthetic applications of gold complexes and the versatility of gold catalysis. Scheme 1. Gold-catalyzed transformations of N-propargylamides.