Photochemical rearrangement of phenyl benzenesulphonates

Abstract

Phenyl benzenesulphonate (Ia) is converted into o- and p-hydroxyphenyl phenyl sulphones and phenol by u.v. irradiation. Quenching and sensitising studies suggest that the rearrangement proceeds via an excited singlet state or via a short-lived triplet. The rearrangement proceeds predominantly via an intramolecular path in view of the results of a mixed reaction involving both (Ia) and p-tolyl toluene-p-sulphonate (Ib) and the effect of radical scavenger. A mechanism involving ‘cage radical pair’ is proposed.