ELECTROCATALYTIC REDUCTION OF BENZAL CHLORIDE BY COBALT(I)(SALEN) - A MECHANISTIC INVESTIGATION

Benzal chloride (6) is converted to a mixture consisting primarily of cis-and trans-stilbene (12) by the action of electrochemically-generated cobalt(I)(salen)-1 (5). The process involves a sequence involving electrocatalytic conversion of benzal chloride to a mixture of the stereoisomeric 1,2-dichloro-1,2-diphenylethanes (10), followed by electrocatalyzed conversion of the latter to 12. Voltammograms of Co(II)(salen) (4) in the presence of varying amounts of 6 exhibit peaks both before and after that due to reduction of 4. The voltammetric data and other chemical evidence is interpreted in light of a previously-suggested mechanism for stilbene formation.