Cuh-catalyzed Enantioselective Intramolecular Reductive Aldol Reactions Generating Three New Contiguous Asymmetric Stereocenters

摘要

Asymmetric reductive aldol reactions provide powerful inroads to stereocontrolled centers of considerable value in synthesis. Invariably, the β-site in an α,β-unsaturated carbonyl derivative either is unsubstituted or at most contains a single E- or Z-substituent. Hence, initial conjugate reduction, regardless of hydride source (e.g., pinacolborane), is of no stereochemical consequence. Rather, the in situ formed nonracemic enolate is the species that controls the subsequent aldol event, thereby giving rise to the anticipated two new centers of central chirality.