Carboxylation of terminal alkynes at ambient CO2 pressure in ethylene carbonate

Abstract

The CuI-catalyzed carboxylation of terminal alkynes with CO₂ and alkyl halides using ethylene carbonate as the solvent under mild conditions was studied. DFT calculations reveal that the energy barrier for CO₂ insertion into the sp-hybridized Cu–C bond could be reduced by employing ethylene carbonate as the solvent. Notably, the procedure was conducted under ambient CO₂ pressure without any external ligands. A broad range of substrates with electron-withdrawing groups or electron-donating groups gave the corresponding products in reasonable yields.