Programming Reaction-Network Bifurcations for Selective Amino Acid Electrosynthesis

Electrosynthesis of organic amino acids from inorganic nitrogen feedstocks offers a new route to expand the synthetic boundaries of biologically relevant C-N molecules. However, the desired organic C-N coupling pathway is kinetically suppressed by the competing inorganic ammonia (NH3) pathway, rendering selective amino acid electrosynthesis intrinsically challenging. Here, we uncover that this bottleneck originates from the uncontrollable gatekeeping intermediate, hydroxylamine (*NH2OH), at the decisive branching point. To address this challenge, we develop a new programmable reaction-network bifurcation (PRNB) strategy, enabled by an atomically precise dual-site metallene, which directs the reaction bifurcation of *NH2OH from hydrogenation to C-N coupling. As a result, the system reverses the product selectivity, allowing the coupling product to outperform NH3 by a factor of 28.5. This shift further achieves glycine synthesis with a high Faradaic efficiency of 83.2% and a formation rate exceeding 885 mmol/gcat/h, sustained over 225 h and enabling gram-scale synthesis. Mechanistic studies reveal that dual sites reprogram the relative bonding preference of *NH2OH, making C-N coupling dominant for oxime formation. In situ spectroscopy and kinetic isotope measurements further reveal that dual sites reorganize an ordered interfacial H2O network that lowers the hydrogen-transfer barrier by more than half, enabling rapid oxime hydrogenation and high-rate glycine production. The efficient synthesis of diverse amino acids, including alanine, glutamate, and leucine, further underscores PRNB as a general paradigm for controlling reaction-network bifurcations in complex chemical synthesis.