THE USE OF ORGANIC-SOLVENT SYSTEMS IN THE YEAST MEDIATED REDUCTION OFETHYL ACETOACETATE

The reduction of ethyl acetoacetate to ethyl (S)-3-hydroxybutyrate, me diated by freeze-dried yeast, proceeds in good yield (53-58%) and with high enantioselectivity (> 96%ee) in a number of organic solvents; pe troleum ether, diethyl ether, toluene, and carbon tetrachloride. A sma ll amount of water (0.8 ml (g-yeast)-1) is required for the reaction t o proceed. The water/yeast/substrate ratio and the solvent polarity ha ve been found to significantly influence the reactivity of the system. The enantiomeric excess was determined by gas chromatography employin g a chiral column.