Electrochemical Reduction of Unsaturated Carbon–carbon Bonds Via 3d Transition-Metal Catalysis

Electrochemical reduction has emerged as a powerful alternative to conventional hydrogenation for unsaturated C–C bonds, enabling precise control without molecular hydrogen or stoichiometric reductants. This review summarizes recent advances in iron-, cobalt-, and nickel-catalyzed electroreduction of alkynes and alkenes, highlighting how electrochemical parameters and catalyst design unlock distinct, controllable reaction manifolds that are inaccessible under thermochemical conditions. These developments position 3d metal electrocatalysis as a versatile and programmable platform for selective hydrogenation and isotopic labeling under mild, sustainable conditions.