Electrocarboxylation of Alkynes with Carbon Dioxide in the Presence of Metal Salt Catalysts

With some common metal salts (CuI, FeCl3) as catalysts, alkynes can be effectively electrocarboxylated with CO2 (4 MPa) in an undivided cell with Ni cathode and Al sacrificial anode containing n-Bu4NBr-DMF as supporting electrolyte with a constant current at room temperature. The saturated tricarboxylic acids besides the dicarboxylic acids were obtained in good yields. The yields of the tricarboxylic acids were strongly influenced by various metal salt catalysts, cathode materials and the property of substituted groups. Finally, the possible electrochemical mechanism was discussed.