Stereochemical control in microbial reduction. 30. Reduction of alkyl 2-oxo-4-phenylbutyrate as precursors of angiotensin converting enzyme (ACE) inhibitors

Alkyl 2-oxo-4-phenylbutyrates are reduced to the corresponding alkyl (R)-2-hydroxy-4-phenylbutyrates, versatile chiral building blocks in organic synthesis, in high chemical yield (80-90%) with excellent stereoselectivity (> 90%ee). The reaction has been run in aqueous diethyl ether at 30 degreesC for 24 h under the catalysis of bakers' yeast (Saccharomyces cerevisiae) which was preincubated for 6 h in the presence of phenacyl chloride. The amount of water in the medium should be controlled strictly not to exceed 0.8 mL (g yeast)(-1).