Fe(III)-Catalyzed Aromatic Hydroxylation with H2O2 in the Presence of a Variety of Electron-Transfer Agents

Abstract Electron-transfer agents such as N,N,N′,N′-tetramethylphenylenediamine (TMPD), ferrocenes, and phenothiazines have been found to mediate the hydroxylation of benzene with H2O2 in the presence of Fe3+. Of these, TMPD catalyst is the most effective to provide phenol in 80% or better yield based on added H2O2 under the optimized conditions. A general mechanism, involving the rate-determining reduction of Fe3+ to Fe2+ with such mediators, is suggested.