Catalytic Asymmetric Aziridination with Catalysts Derived from VAPOL and VANOL

Abstract

This Account describes the discovery and development of the catalytic asymmetric aziridination reaction (AZ reaction) that has been the subject of efforts in our laboratory over the last 12 years. The optimized catalyst system involves catalysts generated from either the VAPOL or VANOL ligand and triphenyl borate. These catalysts are effective for formation of aziridines from the reac­tion of imines that bear a N-benzhydryl substituent with stabilized diazo compounds including the commercially available ethyl diazoacetate (EDA). The reaction is general for N-benzhydryl im­ines prepared from electron-rich and electron-poor aromatic aldehydes, as well as from primary, secondary and tertiary aliphatic aldehydes. This reaction is highly enantioselective and diastereo­selective giving cis-3-substituted aziridine-2-carboxylates in excellent yields. This Account presents the scope of the AZ reaction as defined by the work that has been done in our laboratory up to the present time, as well as applications of the resulting aziridines that have been demonstrated to date.