Mechanism of cyclic carbonate synthesis from epoxides and CO2

Abstract

Three interconnected catalytic cycles account for the title reaction catalyzed by a bimetallic aluminum(salen) complex and Bu4NBr. In the first, Bu4NBr acts as a nucleophile to activate the epoxide. In the second, Bu3N generated in situ serves to activate CO2. In the third, the aluminum (salen) complex brings the two activated species together so that the key bonds can be formed intramolecularly. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.