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

摘要

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 α-methoxycarbonyl-α-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.