Direct Catalytic Asymmetric Doubly Vinylogous Michael Addition of alpha,beta-Unsaturated gamma-Butyrolactams to Dienones

摘要

An asymmetric doubly vinylogous Michael addition (DVMA) of alpha,beta-unsaturated gamma-butyrolactams to sterically congested beta-substituted cyclic dienones with high site-, diastereo-, and enantioselectivity has been achieved. An unprecedented DVMA/vinylogous Michael addition/isomerization cascade reaction affords chiral fused tricyclic gamma-lactams with four newly formed stereocenters.