Mechanism of Cyclic Carbonate Synthesis from Epoxides and CO 2

Abstract Three interconnected catalytic cycles account for the title reaction catalyzed by a bimetallic aluminum(salen) complex and Bu 4 NBr. In the first, Bu 4 NBr acts as a nucleophile to activate the epoxide. In the second, Bu 3 N generated in situ serves to activate CO 2 . In the third, the aluminum(salen) complex brings the two activated species together so that the key bonds can be formed intramolecularly. magnified image