Oxidation of trivalent phosphorus compounds by disulphides

Abstract

When methanol is used as solvent for the reaction between trivalent phosphorus compounds (Ph₂POMe, (MeO)₃P, and Ph₃P) and disulphides (RS·SR), oxidised phosphorus products which do not contain sulphur are obtained when the reaction proceeds by an ionic mechanism. It is suggested that these products are formed by methanolysis of the intermediate phosphonium ions [Ph₂(MeO)·PSR, (MeO)₃PSR, and Ph₃PSR]. The oxidation of triphenylphosphine by thiyl radicals is not affected by the use of alcohols as solvents.