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.