Regime-Switching Control of C–N Bond Evolution in Electrochemical Methylamine Oxidation

Abstract

Electrochemical amine oxidation typically involves competing pathways that govern the fate of C–N bonds, yet selective control over bond preservation, cleavage, and reconstruction remains challenging. Here we demonstrate the first single-substrate electrochemical system enabling switchable synthesis of formamide and N-methylformamide from methylamine as a model amine. Product selectivity can be reversibly switched by independently varying anodic potential, electrolyte composition, or methylamine concentration. Increasing bicarbonate concentration or anodic potential favors formamide formation, whereas increasing methylamine concentration steers the system toward N-methylformamide. In situ infrared spectroscopy and electrochemical mass spectrometry further support the reaction pathways. Isotope-labeling and crossover experiments further uncover distinct carbon-source pathways for formamide and N-methylformamide formation while excluding bicarbonate as a carbon source. Overall, this work establishes a regime-switching strategy for directing electrochemical C–N bond evolution from a single amine feedstock, offering a programmable approach to reaction control at electrified interfaces.