Enzymatic Resolution of Ethyl 3-Hydroxy-3-Phenylpropanoate and Analogs using Hydrolases

This work contributes to the substrate model study of enzymatic hydrolysis of secondary and tertiary beta-hydroxy esters. One secondary and four tertiary beta-hydroxy esters have been employed with PCL, PLE, CRL and AOP enzymes. The best result was observed when PCL was used as an enzyme for the reaction of the secondary ester, ethyl 3-hydroxy-3-phenylpropanoate (1a) (conversion of 50%, ester (R)-1a recovered with 98% e.e. and the acid 1 with 93% e.e. On the other hand, PLE showed the best result for tertiary ethyl 3-hydroxy-3-phenylbutanoate (2a) and ethyl 3-cyclohexyl-3-hydroxy-3-phenylpropanoate (3a), despite the poor selectivity. Ethyl 2-(1-hydroxycyclohexyl)-butanoate (4a) and ethyl 2-(1-hydroxycyclopentyl)-butanoate (5a) were only hydrolyzed by PLE and CRL, but showed no enantioselectivity.