Effects of hydrolysis and esterification side-reactions on the kinetic resolution of enzyme-catalyzed irreversible transesterification in organic solvents

A simplified kinetic model for the enzyme-catalyzed irreversible transesterification in organic solvents was proposed by considering the hydrolysis and esterification side reactions. The analysis was extended to the kinetic resolution of activated racemic esters containing a chiral center in the acid moiety, and was confirmed from the lipase-catalyzed enantioselective transesterification between (R,S)-suprofen 2,2,2-trifluoroethyl ester and 2- N-morpholinoethanol (or di(ethylene glycol)) in cyclohexane. Theoretical analysis indicates that the time-course yield and/or the enantiomeric excess for the desired (S)-ester product may be improved if the employed enzyme has a higher activity and/or enantioselectivity for the hydrolysis and esterification than the transesterification.