OXIDATIVE COUPLING OF SOME 2,6-DISUBSTITUTED PHENOL DERIVATIVES IN PERCHLORIC-ACID MEDIATED BY CERIUM(IV) IONS

2,6-Disubstituted phenol derivatives have been oxidized by cerium(IV) perchlorate in aqueous or aqueous-acetonitrile solutions of perchloric acid as well as in two-phase systems to the corresponding 1,4-benzoqu inones, 4,4'-diphenoquinones, and oligomeric poly(1,4-phenylene) oxide s in good yield. Nature and constitution of the oxidation products as a consequence of reaction conditions and physico-chemical properties o f radicals and radical ions are reported. These properties are discuss ed in terms of stabilities, pK values, and electron densities at carbo n C4 and oxygen.