Enantioselective Radical Construction of 5‑Membered Cyclic Sulfonamides by Metalloradical C–H Amination

Both arylsulfonyl and alkylsulfonyl azides can be effectively activated by the cobalt­(II) complexes of D2-symmetric chiral amidoporphyrins for enantioselective radical 1,5-C–H amination to stereoselectively construct 5-membered cyclic sulfonamides. In addition to C–H bonds with varied electronic properties, the Co­(II)-based metalloradical system features chemoselective amination of allylic C–H bonds and is compatible with heteroaryl groups, producing functionalized 5-membered chiral cyclic sulfonamides in high yields with high enantioselectivities. The unique profile of reactivity and selectivity of the Co­(II)-catalyzed C–H amination is attributed to its underlying stepwise radical mechanism, which is supported by several lines of experimental evidence.