Alcohol dehydrogenase enantiospecificity

Pham, V.T., Phillips, R.S. and Ljungdahl, L.G. (1989) Temperature-dependent enantiospecificity of secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus. J. Am. Chem. Soc., 111, 1935-1936. 

Finally, (S )-coriolic acid (a metabolite of hnoleic acid) has been synthesized, in an enan-tiospecific fashion, by the use of the alcohol dehydrogenase enzyme from baker s yeast in the presence of NADPH. In the key step of this synthesis, the supported enzyme/NADPH was used to reduce a bromovinyl ketone enantiospecifically (equation 71)291. 

Stereoinversion catalyzed by two different alcohol dehydrogenases via enantiospecific oxidation followed by an asymmetric reduction. 

A chemo-enzymatic enantiospecific synthesis of (S)-coriolic acid, (13S)-hy-droxy-18 2(9Z,ll ), mediated via immobilized alcohol dehydrogenase of baker s yeast has been described (31). 15,16-Didehydrocoriolic acid, 13-hydroxy-18 3(9Z, 11E, 15Z), was stereoselectively synthesized starting from pent-2-en-4-yn-1 -ol (32). Four stereoisomers of 9,10,13-trihydroxy-18 l(ll ) were derived from methyl 9,10-epoxy-12-octadecenoate. The latter was obtained by partial epoxidation of methyl linoleate. These trihydroxy C j g fatty acids are potential antirice blast fungal substances (33). (115)-Hydroxy-(125,13S)-epoxy-18 2(9Z,15Z) was synthesized from D-mannose (34). 

Bhalerao, U.T., L. Dasaradhi, C. Muralikrishna, and N.W. Fadnavis, A Novel Chemoen-zymatic Enantiospecific Synthesis of (5)-Coriolic Acid Mediated Via Immobilized Alcohol Dehydrogenase of Baker s Yeast, Tetrahedron Lett. 34 2359-2360 (1993). 

It is well known that various microbial systems are able to deracemise racemic secondary alcohols via a process that generally involves two different alcohol dehydrogenases with complementary enantiospecificity. For example racemic benzoin may be deracemized using Rhizopus oryzae ATCC 9363 (Scheme 4.38). Interestingly, through control of the pH of the medium, it was possible to control the absolute configuration of the major enantiomer produced at pH 7.5-8.S, the (J )-enantiomer was produced in 75% yield and 97% ee whereas at pH 4-5, the (S)-enantiomer was produced in 71% yield and 85% ee [89]. 

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