Asymmetric Synthesis of Highly Substituted β-Lactones through Oxidative Carbene Catalysis with LiCl as Cooperative Lewis Acid

摘要

The reaction of enals with β-diketones, β-ketoesters, and malonates bearing a β-oxyalkyl substituent at the a-position by oxidative NHC catalysis to provide highly substituted β-lactones is described. Reactions occur with excellent diastereo-and enantioselectivity. The organo cascade comprises two C—C bond formations and one C—O bond formation. Up to four contiguous stereogenic centers including two fully substituted stereocenters are formed in the cascade.