Silver-Catalyzed Decarboxylative Trifluoromethylation of Aliphatic Carboxylic Acids

The silver-catalyzed decarboxylative trifluoromethylation of aliphatic carboxylic acids is described. With AgNO3 as the catalyst and K2S2O8 as the oxidant, the reactions of aliphatic carboxylic acids with (bpy)­Cu­(CF3)3 (bpy = 2,2′-bipyridine) and ZnMe2 in aqueous acetonitrile at 40 °C afford the corresponding decarboxylative trifluoromethylation products in good yield. The protocol is applicable to various primary and secondary alkyl carboxylic acids and exhibits wide functional group compatibility. Mechanistic studies reveal the intermediacy of –Cu­(CF3)3Me, which undergoes reductive elimination and subsequent oxidation to give Cu­(CF3)2 as the active species responsible for the trifluoromethylation of alkyl radicals.