Electrochemical Fixation of Carbon Dioxide: Synthesis of Carboxylic Acids

Abstract In the past three decades, we have focused on the fixation of carbon dioxide by electrochemical method with a carbon‐carbon bond forming reaction to yield carboxylic acid, so‐called electrochemical carboxylation. Vinyl bromides and triflates, difluoroethylbenzenes, polyfluoroarenes, benzal diacetates, phenyl‐substituted alkenes and enamides, and α‐aminosulfones were found to be effective as substrates for electrochemical carboxylation. Phenylacetic acids and phenylpropanoic acids including non‐steroidal anti‐inflammatory agents and their fluorinated analogues, polyfluorobenzoic acids, mandel acetates, and α‐ and β‐amino acids were successfully synthesized. Electrochemical double carboxylation of dibenzyl carbonates, reuse of carbon dioxide in benzyl carbonates for fixation of carbon dioxide (recycle‐electrochemical carboxylation), sequential aryl/vinyl radical cyclization‐electrochemical carboxylation, sacrificial anode‐free electrochemical carboxylation, and the use of supercritical carbon dioxide both as a reaction media and a reagent were also developed. In this personal account, our efforts in and results of electrochemical fixation of carbon dioxide to organic compounds with carbon‐carbon bond forming reactions yielding novel and useful carboxylic acids are introduced along with their applications and some new results.