Concise Synthesis of Chiral Tricyclic Lactams by Tandem Dynamic Kinetic Asymmetric Reductive Amination/Lactamization Using Ammonium Salts

摘要

Abstract The atom‐ and step‐efficient synthesis of chiral fused tricyclic lactams from readily available ketoesters using cheap ammonium salts as the nitrogen source is reported. This ruthenium‐catalyzed system operates through an efficient tandem dynamic kinetic asymmetric reductive amination (ARA)/lactamization and produces chiral fused tricyclic lactams in high yields with excellent diastereo‐ and enantioselectivity (up to >99 % ee, >20 : 1 dr and 98 % yield). The robust method was also applied to the concise synthesis of key intermediates in the synthesis of rivastigmine analogues and chiral N‐heterocyclic carbene catalysts.