Metal Acetylacetonates as Robust Catalysts for the Synthesis of Oxazolidinone from CO2 and Aziridine Under Atmospheric Pressure

Metal acetylacetonates, a type of readily synthesized or commercially available metal complex, were demonstrated to be robust catalysts for the synthesis of oxazolidinone from CO2 and aziridine under condition of atmospheric pressure and mild temperature, exhibiting high chemo- and regio-selectivity. Tetrabutylammonium halides were employed as cocatalysts in the reaction, and it was believed that the reaction activity was influenced by a balance of anions’ two abilities, namely their nucleophilicity in ring-opening of aziridines and their leaving capacity in ring-closing of intermediate carbamate salts to form oxazolidinones. Notably, higher nucleophilicity of these anions resulted in increased formation of dimers, which served as by-products of the reaction. The study of mechanism suggested that there should be an alternative pathway involving CO2 derivative acting as a nucleophile during the ring-opening process, and this pathway could not be ignored when conventional nucleophiles, such as tetrabutylammonium halides are absent.