Organocatalytic Stereoconvergent Synthesis of a-CF_3 Amides: Triketopiperazines and Their Heterocyclic Metamorphosis

摘要

The highly enantioselective alkylation of α-CF_3 enolates, generated from triketopiperazines, has been accomplished through use of a bifunctional thiourea organocatalyst to facilitate 1,4-addition to varied enone acceptors. On treatment with appropriate nitrogen nucleophiles, the chiral triketopiperazine products undergo a metamorphosis, to provide novel fused heterocyclic lactams such as extended pyrazolopyrimidines.