Enantioselective Direct α-Annination of Aldehydes via a Photoredox Mechanism: A Strategy for Asymmetric Amine Fragment Coupling

The direct, asymmetric alpha-amination of aldehydes has been accomplished via a combination of photoredox and organocatalysis. Photon-generated N-centered radicals undergo enantioselective alpha-addition to catalytically formed chiral enamines to directly produce stable alpha-amino aldehyde adducts bearing synthetically useful amine substitution patterns. Incorporation of a photolabile group on the amine precursor obviates the need to employ a photoredox catalyst in this transformation. Importantly, this photoinduced transformation allows direct and enantioselective access to alpha-amino aldehyde products that do not require postreaction manipulation.