COSOLVENT ENHANCEMENT OF ENANTIOSELECTIVITY IN LIPASE-CATALYZED HYDROLYSIS OF RACEMIC ESTERS - A PROCESS FOR PRODUCTION OF HOMOCHIRAL C-3 BUILDING-BLOCKS USING LIPASE-B FROM CANDIDA-ANTARCTICA

Lipase-catalysed hydrolysis of butanoates of 3-methoxy-1-(phenylmethox y)-2-propanol and 3-chloro-1-(phenylmethoxy)-2-propanol with various l ipases gave low enantioselectivity, E. By additon of water miscible or ganic cosolvents, in particular tert-butanol and acetone, the E-value was raised from 7 to 220 for the useful chloro derivative. This findin g has led to proposal of a process for production of homochiral C-3 sy nthons such as both enantiomers of phenylmethyl glycidyl ether startin g from racemic epichlorohydrin. NMR studies of lipase B from Candida a ntarctica show that the conformation most likely is not changed upon a ddition of up to 50% acetone. Nuclear Overhauser effects were observed upon irradiation of the phenyl protons of the substrate only in the p resence of enzyme thus indicating an interaction between the two.