Bromide-Mediated Silane Oxidation: A Convenient and Practical Counter-Elecrode Process for Undivided Electrochemical Reductions

The counter-electrode process of an organic electrochemical reaction is integral for the success and sustainability of the process. Unlike for oxidation reactions, there is not a generally practical counter-electrode process for reduction reactions, especially for deep reductions that apply very negative potentials. Herein, we report the development of a bromide mediated silane oxidation counter-electrode process for electrochemical reduction reactions in undivided cells. It is found to be suitable for replacing either sacrificial anodes or the use of a divided cell in several reported reactions. These conditions are metal-free, use inexpensive reagents and a graphite anode, the by-products are reductively stable and readily removed, and the process is demonstrated on large scale in flow.