Photocatalytic C–H functionalization of enamides with N-allylbromodifluoroacetamides via difluoroamidoalkylation and difluoroamidosulfonylation

Abstract

Starting from enamides and N-allylbromodifluoroacetamides, two distinct photocatalyzed cyclization/functionalization strategies have been devised to efficiently introduce a 3,3-difluoro-γ-lactam unit into trifunctionalized enamides. Through these approaches, a collection of 38 trisubstituted amides bearing an absolute (E)-configuration was synthesized with acceptable yields. The visible-light-driven difluoroamidoalkylation and three-component difluoroamidosulfonylation processes both rely on two fundamental mechanisms: intramolecular radical relay and subsequent intermolecular radical interaction. These photocatalytic transformations are characterized by their broad substrate applicability, remarkable compatibility with diverse functional groups, mild reaction conditions, and exceptional regio- and stereoselectivity.