Regioselective Synthesis of Benzazetines and Indoles from Alkenylanilides and Dimethyl(methylthio)sulfonium Trifluoromethanesulfonate

Abstract Regioselective synthesis of benzazetines and indoles from o-alkenylanilides was achieved. The reaction of o-vinylbenzanilide with dimethyl(methylthio)sulfonium trifluoromethanesulfonate (DMTST) gave the corresponding benzazetine in 92% yield, whereas the reaction of o-vinyl-N-p-toluenesulfonylanilide gave N-tosylindoline in 77% yield. 3-Methy-N-p-tosylindole was directly synthesized by the reaction of o-isopropenyl-N-p-tosylanilide with dimethyl disulfide and methyl triflate in 85% yield.