Construction of Quaternary Carbon Center by Catalytic Asymmetric Alkylation of 3-Arylpiperidin-2-ones Under Phase-Transfer Conditions

A highly enantioselective synthesis of delta-lactams having a chiral quaternary carbon center at the alpha-position has been developed through an asymmetric alkylation of 3-arylpiperidin-2-ones under phase-transfer conditions. In this transformation, a 2,2-diarylvinyl group on the delta-lactam nitrogen atom plays a crucial role as a novel protecting group and an achiral auxiliary for improving both yield and enantioselectivity of the reaction.