Palladium-Catalyzed Decarbonylative C–H Difluoromethylation of Azoles

A (XantPhos)Pd-catalyzed decarbonylative C-H functionalization of azoles with difluoromethyl anhydrides is reported. Under the optimized conditions, azole substrates react selectively at the C(2)-position to afford CF2H-substituted benzoxazole, oxazole, benzothiazole, thiazole, and benzimidazole products. Organometallic mechanistic studies reveal that XantPhos enforces an unusual seesaw geometry of the key PdII(CF2H)(carboxylate) intermediate, which may be responsible for the effectiveness of this ligand.