Highly Enantioselective Resolution of beta-Amino Esters by Candida antarctica Lipase A Immobilized in Mesocellular Foam: Application to Dynamic Kinetic Resolution

Candida antarctica lipase A (CALA) immobilized in functionalized mesocellular foam in the presence of sucrose, followed by lyophilization, led to a dramatic increase in the enantioselectivity as well as an improved thermostability of the enzyme. The immobilized lipase was used for kinetic resolution (KR) and dynamic kinetic resolution (DKR) of the beta-amino ester, ethyl 3-amino-3-phenylpropanoate. The temperature of optimum activity of CALA shifted from 20-30 degrees C to 80-90 degrees C on immobilization in the MCF. An enantiomeric ratio E (E=nu(A)/nu(B); nu(A) and vs are the rate constants for entantiomers A and B) of 69 and a conversion of 43% in 1 h were obtained at 80 degrees C, whereas non-immobilized CALA lost its activity at T >= 50 degrees C. The obtained immobilized CALA showed an E value of greater than 500 at 22 degrees C. Combination of the immobilized CALA with a ruthenium complex, acting as a racemization catalyst, allowed for a successful DKR of ethyl 3-amino-3-phenylpropanoate resulting in 85% conversion and 89% ee.