Acyloxylation of methylbenzenes by potassium peroxydisulphate

Abstract

Potassium peroxydisulphate in acetic acid containing 9% trifluoroacetic acid has been shown to oxidize a number of substituted methylbenzenes, yielding nuclear and side-chain acetates. In the presence of copper(II) acetate nuclear substitution is suppressed, and a mixture of side-chain acetate and trifluoroacetates is obtained. This mixture can be hydrolysed to the corresponding benzyl alcohol in total yields varying from 18 to 66%. The mechanism has been investigated and the results obtained support a radical cation pathway.