This work contributes to the substrate model study of enzymatic hydrolysis
of secondary and tertiary beta -hydroxy esters. One secondary and four tert
iary beta -hydroxy esters have been employed with PCL, PLE, CRL and AOP enz
ymes. The best result was observed when PCL was used as an enzyme for the r
eaction of the secondary ester, ethyl 3-hydroxy-3-phenylpropanoate (1a) (co
nversion of 50%, ester (R)-1a recovered with 98% e.e. and the acid 1 with 9
3% 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-phenylpro
panoate (3a), despite the poor selectivity. Ethyl 2-(1-hydroxycyclohexyl)-b
utanoate (4a) and ethyl 2-(1-hydroxycyclopentyl)-butanoate (5a) were only h
ydrolyzed by PLE and CRL, but showed no enantioselectivity.