Electrochemical reduction of cinnamonitrile in the presence of carbon dioxide: Synthesis of cyano- and phenyl-substituted propionic acids

Cyano- and phenyl-substituted propionic acids were synthesized simply and efficiently by electrocarboxylation of cinnamonitrile in undivided cells using the non-noble metal nickel as cathode and magnesium as the anode. The radical anion generated by the electroreduction of cinnamonitrile in the absence of CO₂ is involved in several competitive reactions that lead to the formation of linear hydrodimers, cyclic hydrodimers, saturated dihydro products, and glutaronitrile derivatives. While under 101.325 kPa of CO₂, the electrocarboxylation could easily be carried out in the absence of additional catalysts, and with good yield (84.8%). The influence of various synthetic parameters, such as the nature of the electrode, the working potential, the concentration, and the temperature, on the electrocarboxylation reaction was investigated.