Pyrolysis of styryl sulphoxides and sulphides. Formation of benzothiophen derivatives via intramolecular cyclization of thiyl radicals

Abstract

The pyrolysis of styryl sulphoxides yields benzothiophens in 40–50% yield, indicating that intra-molecular cyclization of the styrylthiyl radical, which may be formed by homolysis of the S–OH bond of an inter-mediate sulphenic acid, is a favourable process; pyrolysis of styryl sulphides, and bis-(β-methyl styryl) disulphide also gave benzothiophens under similar conditions.