Bifunctional N-heterocyclic carbene ligands for Cu-catalyzed direct C-H carboxylation with CO2

Abstract

Diethylene glycol-functionalized imidazo[1,5-a] pyridin-3-ylidenes (DEG-ImPy) have been developed as bifunctional N-heterocyclic carbene ligands. The DEG-ImPy Cu(I) complexes efficiently catalyzed the direct C-H carboxylation of benzoxazole with CO2, showing higher isolated yields than those with the N,N'-(2,6-diisopropylphenyl) imidazolylidene Cu catalyst.