Copper-Photocatalyzed Selective α-C(sp³)-H Sulfonylation of Amides with Sodium Sulfinates via 1,5-Hydrogen Atom Transfer

The development of a general and selective method for α-C(sp³)-H sulfonylation of amides is challenging via conventional methods. Herein, a visible-light-induced, copper-catalyzed protocol for the mild and eco-friendly α-C(sp³)-H sulfonylation of amides with sodium sulfinates has been developed. The activation of 2-iodobenzamide by the (4-Tol)₂-BINAP copper complex to generate aryl radicals and the intramolecular 1,5-HAT process to produce α-amidoalkyl radicals are the key to the success of this chemistry. A wide range of 2-iodobenzamides and sodium sulfinates was well-tolerated and afforded sulfonylation products with up to 86% isolated yield. In addition, the reaction could be readily scaled up and the products were successfully used for further synthetic transformations.