Iron-Catalyzed, Site-Selective Difluoromethylthiolation (-SCFH) and Difluoromethylselenation (-SeCFH) of Unactivated C(sp)-H Bonds in -Fluoroamides.

The iron-catalyzed δ-C(sp)-H bond difluoromethylthiolation and difluoromethylselenation of aliphatic amides with high site selectivity are reported. Essential to the success is the employment of an amide radical formed in situ to activate the inert C(sp)-H bond and the utilization of the easily handled PhSOSCFH and PhSOSeCFH as coupling reagents under mild conditions. This scalable protocol exhibits a broad substrate scope bearing versatile functional groups. Mechanistic studies indicate that the reaction proceeds through -SCFH and -SeCFH radical transfer.