Asymmetric Disulfonimide-Catalyzed Synthesis of delta-Amino-beta-Ketoester Derivatives by Vinylogous Mukaiyama-Mannich Reactions

摘要

An organocatalytic asymmetric synthesis of delta-amino-beta-ketoester derivatives has been developed. A chiral disulfonimide (DSI) serves as a highly efficient precatalyst for a vinylogous Mukaiyama-Mannich reaction of readily available dioxinone-derived silyloxydienes with N-Boc-protected imines, delivering products in excellent yields and enantioselectivities. The synthetic utility of this reaction is illustrated in various transformations, including a new C-C bond-forming reaction, which provide useful enantioenriched building blocks. The methodology is applied in a formal synthesis of (-)-lasubin.