Stereoselective radical C–H alkylation with acceptor/acceptor-substituted diazo reagents via Co(ii)-based metalloradical catalysis† †Electronic supplementary information (ESI) available. CCDC 1020629–1020631. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4sc02610a Click here for additional data file. Click here for additional data file.

Co(II)-based metalloradical catalysis has been, for the first time, successfully applied for asymmetric intramolecular C-H alkylation of acceptor/acceptor-substituted diazo reagents. Through the design and synthesis of a new D2-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 diastereoselectivity and enantioselectivity. 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.