Cycloaddition of carbon dioxide and epoxides catalyzed by rare earth metal complexes bearing a Trost ligand

A series of rare earth metal complexes (Sm (1), Eu (2), Y (3), Yb (4), and Lu (5)) based on Trost ligands were synthesized and well characterized, and catalyzed the cycloaddition of carbon dioxide and epoxides successfully. The combination of 1 mol% Sm-based complex 1 with 2 mol% tetrabutylammonium bromide (TBAB) was proved to be the optimal catalyst system for the formation of the monosubstituted cyclic carbonate at 70 degrees C under the atmospheric pressure. While for the more challenging disubstituted epoxides, the adduct cyclic carbonates were successfully obtained when the pressure of CO2 was elevated to 0.7 MPa.

Automated summary

A series of rare earth metal complexes based on Trost ligands were synthesized and successfully catalyzed the cycloaddition of carbon dioxide and epoxides. The optimal catalyst system was found to be 1 mol% Sm-based complex 1 with 2 mol% TBAB, forming monosubstituted cyclic carbonate at 70 degrees C. For the more challenging disubstituted epoxides, cyclic carbonates were obtained at elevated CO2 pressure of 0.7 MPa.