Formation of Chiral All-Carbon Quaternary Stereocenters by Photoinduced Cobalt-Catalyzed Enantioselective Radical Coupling

Photoinduced enantioselective strategies provide an efficient way to access chiral all-carbon quaternary stereocenters. Compared with the well-developed metal-catalyzed asymmetric conjugate addition of organometallic reagents to enones, the construction of chiral all-carbon quaternary stereocenters through a radical process still remains challenging, especially for the acyclic enones due to their enhanced conformational mobility. Herein, we disclose a photoinduced cobalt-catalyzed asymmetric radical coupling of α,β -unsaturated 2-acyl imidazoles and α-silylamines to give β,β -disubstituted γ-amino acid derivatives with acyclic quaternary carbon stereocenters. The facile protocol shows good functional group tolerance and a broad substrate scope. The corresponding chiral products were obtained in generally good yields (up to 96%) with high enantioselectivities (up to 99:1 e.r.).