A Difluoromethylation Reagent: Access to Difluoromethyl Arenes through Palladium Catalysis.

A new radical difluoromethylation was developed by using inexpensive and readily available difluoroacetic anhydride and -phenyl-4-methylbenzenesulfonamide for the first time. The reaction of arylboronic acids with the new difluoromethylation reagent, -phenyl--tosyldifluoroacetamide, proceeded smoothly in the presence of palladium catalyst to provide difluoromethylarenes in satisfactory to excellent yields. The electronic property (electron-donating or electron-withdrawing) of the substituent linked to the aromatic ring did not considerably influence the reactivity of arylboronic acid. Various groups, including the synthetically useful functional groups Cl, CN, and NO, were tolerated well under the current reaction conditions.