Electrochemical methods enable the controlled generation of reactive radical intermediates, yet mechanistic interrogations of such transformations remain challenging due to the dynamic, heterogeneous nature of these systems. Here we report a simple, commercially accessible operando electrochemical NMR (EC-NMR) platform adapted from a Bruker InsightMR® flow unit for real-time monitoring of electrochemical reactions. Integration of a batch electrochemical cell with an NMR flow tube allows continuous circulation and quantitative acquisition of 1H NMR spectra under the reaction conditions. This analytical tool helped to elucidate the chemoselectivity of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-mediated allene dioxygenation and revealed off-cycle pathways in the Shono oxidation. Extended monitoring of an electroreductive imine coupling further demonstrated the robustness of this approach. Overall, operando EC-NMR offers a powerful tool for kinetic analysis in synthetic electrochemistry.
Lee et al. (Thu,) studied this question.