Bis(oxalato)borate Salts as Safe and Fluorine‐Free Alternatives to Conventional Supporting Electrolytes for Organic Electrosynthesis

Supporting electrolytes are indispensable in organic electrosynthesis, since they provide the ionic conductivity required for closing the electrical circuit. In combination with organic solvents, lithium or tetraalkylammonium salts of perchlorate, tetrafluoroborate, and hexafluorophosphate are typically employed. Although these salts exhibit good solubility and high electrochemical stability, there are known issues with chemical stability, safety, and sustainability. Therefore, problems are to be expected when transferring lab‐scale innovations to industrial application, which is why sustainable and affordable alternatives with comparative performance are needed. In this context, we explored the use of commercially available lithium bis(oxalato)borate as potential candidate. In the present work, we compare the (electro)chemical properties to the standard salts in typical reaction media and characterize the performance in electrosynthesis using three different test cases. It was found that LiBOB can compete with LiClO 4 , LiPF 6 , and LiBF 4 in terms of electrochemical stability and ionic conductivity. Anodic synthesis of diaryliodonium compounds, cathodic ketone reduction, and TEMPO‐mediated oxidation of alcohols were selected as test reactions, showing that product yields are comparable to the ones obtained with conventional salts. Analysis of the post‐electrolysis reaction mixtures showed that the BOB anion remains intact throughout electrolysis when aprotic electrolytes are used.