Photo-sensitized oxidation of sulphur and pyridinium ylides. Oxygen atom transfer to divalent sulphur

Abstract

Methylene Blue sensitized photo-oxidation of dimethyl oxosulphonium and pyridinium bis(methoxycarbonyl)methylides in chloroform gave dimethyl sulphoxide and pyridine as the main products respectively, together with dimethyl mesoxalate; the photo-oxidation of diphenyl sulphide afforded diphenyl sulphoxide, and the results indicate that an oxygen atom is transferred to diphenyl sulphide from oxenoid rather than from 1,2-dioxetan intermediates.