Visible-Light-Induced Chemoselective Dicarboxylation of Alkynes Using Formate and CO2

Abstract

Visible-light-induced dicarboxylation of alkynes with carbon dioxide (CO2) and formate for the synthesis of succinic acids has been developed. The formate salt acts as both a carboxyl source and reductant in the reaction with catalytic amount of 1,4-diazabicyclo[2.2.2]octane (DABCO) as a hydrogen atom transfer reagent. Various internal alkynes and terminal alkynes could be converted to the corresponding dicarboxylic acids under mild reaction conditions at ambient temperature. Mechanistic experiments were conducted to prove that the reaction undergoes a pathway involving carbon dioxide radical anion (CO2•−) from the low-cost formate.