Electrocatalytic C─C Bond Formation Via Cyanide Interception of CO 2 Reduction Intermediates

ABSTRACT Electrochemical CO 2 reduction offers a sustainable route to convert greenhouse gas into high‐value‐added chemicals, yet product distributions remain largely limited to simple C 1 ‐C 3 molecules. Here, we report a new reaction in which CO 2 reduction intermediates undergo direct C‐C coupling with an external carbon nucleophile under electrochemical conditions. Using cobalt phthalocyanine supported on multi‐walled carbon nanotubes (CoPc/MWCNT) as a catalyst, cyanide ions intercept deeply reduced C 1 intermediates to produce glycolonitrile at 4°C with a faradaic efficiency (FE) of up to 6.6%. Combined electrochemical analysis, control experiments, and density functional theory calculations identify *CH 2 O as the key coupling intermediate, revealing a C‐C coupling mechanism fundamentally different from conventional coupling pathways in CO 2 electroreduction to synthesize C 2+ compounds. Extending this concept to a three‐component reaction involving hydroxylamine (NH 2 OH) enables electrocatalytic synthesis of glycine under ambient pressure with a FE of 2.8%. This work establishes a new strategy for constructing complex carbon skeletons directly from CO 2 and external nucleophiles, expanding the synthetic scope of electrochemical carbon conversion.