Copper-Catalyzed Intermolecular Functionalization of Unactivated C(sp)-H Bonds and Aliphatic Carboxylic Acids.

Intermolecular functionalization of C(sp)-H bonds and aliphatic carboxylic acids enables the efficient synthesis of high value-added organic compounds from readily available starting materials. Although methods involving hydrogen atom transfer have been developed for such functionalization, these methods either work for only activated C(sp)-H bonds or bring in a narrow set of functional groups. Here we describe a Cu-catalyzed process for the diverse functionalization of both unactivated C(sp)-H bonds and aliphatic carboxylic acids. The process is enabled by the trapping of alkyl radicals generated through hydrogen atom abstraction by arylsulfonyl-based SOMO-philes, which introduces a large array of C, N, S, Se, and halide-based functional groups. The chemoselectivity can be switched from C-H functionalization to decarboxylative functionalization by matching the bond dissociation energy of the hydrogen atom transfer reagent with that of the target C-H or O-H bond.