A chiral, bimetallic cobalt(III)salen-calix[4]arene hybrid structure was prepared and tested in the hydrolytic kinetic resolution (HKR) of racemic epoxides. Kinetic studies have revealed that the two catalytic units on the upper rim of the calixarene scaffold are able to activate the reactants in a cooperative and primarily intramolecular mode. High enantioselective behaviour was observed and besides, a higher stability was found for the bimetallic catalyst as compared to a monometallic reference complex.
Cooperative activation in the hydrolytic kinetic resolution of epoxides by a bis-cobalt(III)salen-calix[4]arene hybrid
Adv. Synth. Catal. 2010, 352, 85-91.