Electrochemical oxidation of hydroquinone and catechols has been studied in the presence of triphenylphosphine (3) as a nucleophile in water/acetonitrile (40/60) solutions using cyclic voltammetry and controlled-potential coulometry. The results indicate that quinones derived from oxidation of hydroquinone or catechols, participate in a conjugate addition reaction with triphenylphosphine (3) via an EC mechanism, converting them to corresponding organophosphorus derivatives. In this work, we prepared C-phosphoniumquinol betaine compounds in good yields using at controlled-potential electrochemical oxidation at a carbon electrode in a divided cell. (C) 2008 Elsevier B.V. All rights reserved.