Palladium-Catalyzed Trifluoroacetylation of Arylboronic Acids Using a Trifluoroacetylation Reagent.

A new trifluoroacetylation reagent was developed by using inexpensive and readily available trifluoroacetic anhydride and -phenyl-4-methylbenzenesulfonamide for the first time. The reaction of (het)aryl boronic acids with the new trifluoroacetylation reagent, -phenyl--tosyltrifluoroacetamide, proceeded smoothly in the presence of a palladium catalyst to provide trifluoromethyl ketones in satisfactory to excellent yields. Various groups, including the synthetically useful functional groups Cl, TMS, and PhCO, were tolerated well under the current reaction conditions. This new trifluoroacetylation reagent can be used in the large-scale synthesis of trifluoromethyl ketones, even at a low palladium catalyst loading.