Microbial Deracemization of Secondary Alcohols Using a Single Microorganism

Microbial Deracemization of Secondary Alcohols Using a Single Microorganism 

It is well known that certain microorganisms are able to effect the deracemization of racemic secondary alcohols with a high yield of enantiomerically enriched compounds. These deracemization processes often involve two different alcohol dehydrogenases with complementary enantiospedficity. In this context Porto ef al. [24] have shown that various fungi, induding Aspergillus terreus CCT 3320 and A. terreus CCT 4083, are able to deracemize ortho- and meta-fluorophenyl-l-ethanol in good 

Deracemization of Alcohols Using Two Enzyme/Microorganism Systems 

100% ee and a respectable 91% yield, whereas the Y. lipolytica supernatant gave poor results (40% ee and 85% yield). 

Using this approach, racemates of (27) were enantiomerically enriched using a lipase in organic solvent, followed by racemization of the unreacted enantiomer in buffer. Acylated derivatives (S)-(28) were obtained in yields 50% and 99% ee. Lipases with the opposite enantioselectivity produced (R)-28 in 99% ee. Subsequent chemical deacylation of (28) yielded enantiomerically enriched (27). 

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