Copper-Catalyzed, Interrupted Remote Fluoromethylthiolation of Unactivated C(sp3)-H Bonds.

An efficient copper-catalyzed selective fluoromethylthiolation of an inert δ-C(sp ³ )-H bond in sulfonamides was reported. In the presence of a copper catalyst and PhSO ₂ SR _f , the radical generated through 1,5-hydrogen atom transfer (HAT) was sufficiently trapped by PhSO ₂ SR _f , instead of copper, which was prevalent in metal-catalyzed radical-relay processes, incorporating a fluoromethylthio group into molecules. The general substrate scope and mild conditions endowed the method with wide potential applications in pharmaceuticals and agrochemicals.