Light‐Driven Enantioselective Carbene‐Catalyzed Radical‐Radical Coupling

Abstract An enantioselective carbene‐catalyzed radical‐radical coupling of acyl imidazoles and racemi c Hantzsch esters is disclosed. This method involves the coupling of an N‐heterocyclic carbene‐derived ketyl radical and a secondary sp 3 ‐carbon radical and allows access to chiral α‐aryl aliphatic ketones in moderate‐to‐good yields and enantioselectivities without any competitive epimerization. The utility of this protocol is highlighted by the late‐stage functionalization of various pharmaceutical compounds and is further demonstrated by the transformation of the enantioenriched products to biologically relevant molecules. Computational investigations reveal the N‐heterocyclic carbene controls the double‐facial selectivity of the ketyl radical and the alkyl radicals, respectively.