Folic Acid Promoted the Coupling Reaction of Epoxides and CO2

The process of hydrogen bond donor accelerating the cycloaddition of epoxides with CO2 is green access to high economic value cyclocarbonate derivatives. However, hydrogen bond donor still has certain limitations such as poor biocompatibility and narrow substrate scope. Our group found that folic acid could promote the coupling reaction of epoxides and CO2 through hydrogen-bonding. The reaction was used to synthesize various cyclocarbonate derivatives in good to high yields with the aid of folic acid and TBAB. In addition, benzoic acids and 2,4-quinazoline dione were synthesized in the presence of CuCl2/folic acid and PdCl2/folic acid, respectively. The reaction mechanism was proposed based on previous reports and control experiments.