Reduction mechanism of benzoin on a mercury electrode

The electrochemical reduction of benzoin was studied in acid media at DME. Convolution potential sweep voltammetry was applied to obtain the charge transfer rate constants. The overall reduction corresponds formally to an irreversible two-electron, two-proton transfer. Deoxybenzoin was identified as the final product of the benzoin reduction. Low-temperature bulk electrolysis experiments showed the presence of an unstable enol intermediate. This compound undergoes an enol-keto transformation, whose acid catalyzed rate constants were determined by chronoamperometry. The kinetic results indicate a stabilization of the intermediate carbocation in the presence of perchlorate. (C) 1997 Elsevier Science S.A.