Metal catalysis in oxidation by peroxides. Part 15. Steric effects in the oxidation of organic sulphides with V(V) and Mo(VI) peroxo complexes

Abstract

The rates of oxidation to the corresponding sulphoxides of two dialkyl sulphides, Bu n—S—Bu n and Bu n—S—Bu t, and two arylalkyl sulphides, Ph—S—CH 3 and Ph—S—Bu t, with t-butylhydroperoxide and hydrogen peroxide in the presence of catalytic amounts of vanadium (VO(acac) 2) and molybdenum (MoO 2(acac) 2), have been measured in ethanol. The steric retardations observed are compared with those previously found in the acid-catalyzed oxidation of the same substrates, with hydrogen peroxide in ethanol, a typical ‘electrophilic’ oxidation. This comparison indicates very similar behaviour of the various oxidizing systems, thus confirming the generality of the external ‘electrophilic’ oxidation by metalperoxo species.