CHEMOMETRIC OPTIMIZATION OF AN ASYMMETRIC REDUCTION CATALYZED BY BAKERS-YEAST

The stereoselective reduction of ethyl acetoacetate to (+)‐(S)‐ethyl 3‐hydroxybutyrate catalyzed by Saccharomyces cerevisiae was optimized by means of chemometric methods. The quantitative effects of temperature, time of incubation, and concentrations of yeast and substrate on the optical purity and on the percent of reduced substrate were investigated using a factorial design at two levels. This approach gave information about the chemical behavior of the catalyst. The variability of the two responses was expressed by means of their corresponding response surfaces. Use of desirability functions allowed the overall optimization of the process, also taking into account the importance of economic factors. The investigation showed that it is possible to reduce the substrate completely obtaining (+)‐(S)‐ethyl 3‐hydroxybutyrate with percent of enantiomeric excess>98% and, at the same time, to operate in more convenient experimental conditions than those previously reported. Copyright © 1990 John Wiley & Sons, Inc.