Enantioselective Synthesis of cis-4-Formyl-β-lactams via Chiral N-Heterocyclic Carbene-Catalyzed Kinetic Resolution

An efficient synthesis of optically pure cis-4-formyl-β-lactams (up to 99% ee) by a chiral NHC-catalyzed ring expansion reaction has been realized, featuring the ready availability of both the substrate and the catalyst, and the mild reaction conditions. The current method is also suitable for the synthesis of enantioenriched 4-formyl-β-lactams and succinimides containing quaternary carbon centers.