Intramolecular cyclization using methyl(bismethylthio)sulphonium salts. Part 1. 2,3-Dihydrobenzofurans

Abstract

Methyl(bismethylthio)sulphonium hexachloroantimonate (1a) reacts under mild conditions with 2-allylphenol (3a) to give 2-(methylthiomethyl)-2,3-dihydrobenzofuran (4a). Methylthiolation at position 5 in the heterocycle may also occur. With 4-substituted 2-allylphenols (3b–d)(substituents: methyl,chloro,nitro) only the corresponding 5-substituted 2-(methylthiomethyl)-2,3-dihydrobenzofurans (4b–d) are obtained.