Copper(I)@Carbon-Catalyzed Carboxylation of Terminal Alkynes with CO₂ at Atmospheric Pressure

Activated carbon supported CuBr was found to be an efficient catalyst for the carboxylation of terminal alkynes under atmospheric pressure of CO₂ using ethylene carbonate as solvent at 80 °C for only 2 h, as verified with ¹³CO₂. Various terminal alkynes could react smoothly with CO₂ and organic halides under the reaction conditions to afford the corresponding carboxylic esters. In addition, the catalyst can be easily recovered and reused at least five times without significant loss of activity