Stereoselective radical C-H alkylation with acceptor/acceptor-substituted diazo reagents via Co(II)-based metalloradical catalysis

Co(II)-based metalloradical catalysis has, for the first time, been successfully applied for asymmetric intramolecular C-H alkylation of acceptor/acceptor-substituted diazo reagents. Through the design and synthesis of a new D-2-symmetric chiral amidoporphyrin as the supporting ligand, the Co(II)-based metalloradical system, which operates at room temperature, is capable of 1,5-C-H alkylation of alpha-methoxycarbonyl-alpha-diazosulfones with a broad range of electronic properties, providing the 5-membered sulfolane derivatives in high yields with excellent diastereoselectivities and enantioselectivities. In addition to complete chemoselectivity toward allylic and allenic C-H bonds, the Co(II)-based metalloradical catalysis for asymmetric C-H alkylation features a remarkable degree of functional group tolerance.