Applications of high-potential quinones. Part VIII. Mechanism of oxidation of 2-benzylphenol to benzylbenzoquinones

Abstract

One-electron oxidation of 2-benzylphenol by 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) in alcoholic solvents leads to the coupled adduct (5), together with 2-alkoxy-6-benzyl-1,4-benzoquinones. The alkoxyquinones (8) and (9) are formed from the adduct (5)via 2-benzyl-1,4-benzoquinone (11), which undergoes DDQ-catalysed addition of the alcohol at C-6. The regiospecificity of nucleophilic attack in this latter reaction is explained by steric inhibition to co-ordination of the catalyst at the C-1 carbonyl oxygen atom.