Chemistry of sulphenates in acidic media

Abstract

Methyl toluene-p-sulphenate is hydrolysed rapidly in moist solvents (dioxan, benzene, chloroform, or nitrobenzene) yielding methyl toluene-p-sulphinate, di-p-tolyl disulphide, and methanol. The reaction is acid catalysed. At higher concentration of water (>1%) the products are: p-tolyl toluene-p-thiolsulphonate, di-p-tolyl disulphide, and methanol. A mechanism is suggested where thiolsulphinate, which is usually suggested as the intermediate in the hydrolysis of sulphenyl derivatives, combines with unchanged sulphenate ester to yield an intermediate sulphonium salt. The sulphonium slat then rapidly reacts with either methanol or water to yield the products. Some implications for the chemistry of sulphenic acids are also discussed.