Electrochemical N-Formylation of Amines: Mechanistic Insights and Sustainable Synthesis of Formamides via a Methylisocyanide Intermediate

Electrochemical methodologies offer a transformative approach to sustainable chemical synthesis by enabling precise, energy-efficient transformations. Here, we report the selective electrochemical N-formylation of methylamine using methanol as both reagent and solvent, facilitated by a simple glassy carbon electrode. Under optimized conditions, we achieve a faradaic efficiency (FE) of 34% for methylformamide synthesis in a neutral NaClO₄ electrolyte. Mechanistic insights from in situ Fourier-transform infrared spectroscopy (FTIR) and complementary synthetic experiments reveal two distinct reaction pathways: the direct oxidation of a hemiaminal intermediate and a novel route involving the formation of methylisocyanide, which subsequently hydrates to yield methylformamide. The presence of methylisocyanide was confirmed through mass spectrometry analysis following a successful Ugi multicomponent reaction, demonstrating the ability to safely utilize reactive intermediates within an electrochemical framework. This work underscores the potential of electrosynthesis to unlock metal-free, sustainable pathways to produce value-added nitrogen-containing compounds, paving the way for greener approaches in chemical manufacturing and catalysis.