Bromide-Mediated Silane Oxidation: A Practical Counter-Electrode Process for Nonaqueous Deep Reductive Electrosynthesis.

The counter-electrode process of an organic electrochemical reaction is integral for the success and sustainability of the process. Unlike for oxidation reactions, counter-electrode processes for reduction reactions remain limited, especially for deep reductions that apply very negative potentials. Herein, we report the development of a bromide-mediated silane oxidation counter-electrode process for nonaqueous electrochemical reduction reactions in undivided cells. The system is found to be suitable for replacing either sacrificial anodes or a divided cell in several reported reactions. The conditions are metal-free, use inexpensive reagents and a graphite anode, are scalable, and the byproducts are reductively stable and readily removed. We showcase the translation of a previously reported divided cell reaction to a >100 g scale in continuous flow.