Novel formation of indoles and 3,1-benzoxazines from o-alkenylanilides and dimethyl(methylthio)sulfonium trifluoromethanesulfonate

The reaction of dimethyl(methylthio)sulfonium trifluoromethanesulfonate (DMTST) with o-allylphenol gave 2-methylthiomethyl-2,3-dihydrobenzofuran in 97% yield. The reaction of DMTST with N-tosyl-o-isopropenylanilide followed by the addition of aq sodium carbonate afforded N-tosyl-3-methylindole in 88% yield, whereas N-tosyl-o-vinylanilide afforded N-tosylindoline in 85% yield.