CATHODIC CLEAVAGE OF CARBON-OXYGEN BONDS .5. DIRECT AND INDIRECT ELECTROCHEMICAL REDUCTION OF EPOXIDES

The electrochemical behaviour of the epoxides having the structure {A figure is presented} with R being an aromatic ring (or any unsaturated system) is described in the couple: DMF-tetraalkylammonium salts on a mercury cathode. The opening of the ring corresponds to a two-electron mechanism but further cleavages of C-O bonds are observable. Indirect reduction of the epoxide by means of an electrogenerated anion-radical or/and dianion of some well chosen mediators is also possible. In some cases, the redox catalysis can also be autocatalysed when the opening is followed by an elimination with production of an unsaturated hydrocarbon which is able to lead rapidly to a stable anion-radical which then plays the rǒle of reducing of the starting material in homogeneous phase. © 1979.