Metal-Free Trifluoromethylation and Arylation of Alkenes: Domino Synthesis of Oxindole Derivatives

A novel, simple and highly efficient method for the synthesis of 3-(trifluoromethyl)-indolin-2-one derivatives has been developed. The protocol uses readily available N-alkyl-N-phenylacrylamides as the starting materials, inexpensive and easily stored Langlois reagent (sodium trifluoromethanesulfinate) as the trifluoromethyl source, and iodobenzene diacetate [PhI(OAc)(2)] as the oxidant. The procedure involves a metal-free domino trifluoromethylation and arylation of alkenes. The methods did not need mediation of any transition metal which avoided contaminations of toxic metals in the products.