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 Pd^II(CF₂H)(carboxylate) intermediate, which may be responsible for the effectiveness of this ligand.