Catalytic enantioselective synthesis of β-lactams:: Intramolecular Kinugasa reactions and interception of an intermediate in the reaction cascade

A planar-chiral Cu/phosphaferroceneoxazoline catalyst mediates intramolecular Kinugasa reactions to give tricyclic β-lactams with good enantioselectivity. A variant of the process, in which a postulated enolate intermediate is intercepted with an electrophile in a transformation that generates two C-C bonds, a C-N bond, two new rings, a carbonyl group, and adjacent tertiary and quaternary stereocenters (see scheme), supports the proposed mechanism.