Asymmetric reduction of substituted α- and β-ketoesters by Bacillus pumilus Phe-C3

The enantioselective reduction of substituted α- and β-ketoesters using resting cells of Bacillus pumilus Phe-C3 was investigated. Effects of substrate concentration on the catalytic efficiency of the microorganism were studied. Preparative scale productions were carried out under the optimized conditions with 62.4–91.0% yields and 90.2–97.1% ee. The cells retained 80% of initial activity after recycling for six times.

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Ethyl (R)-3-hydroxybutyrateC6H12O3Ee = 94.5% by chiral GC with a CP-Chirasil-Dex-CB column[α]D25=-43.1 (c 1.0, CHCl3)Source of chirality: Bacillus pumilus Phe-C3 alcohol dehydrogenaseAbsolute configuration: (3R)

Ethyl (S)-4-chloro-3-hydroxybutyrateC6H11O3ClEe = 95.9% by chiral GC with a CP-Chirasil-Dex-CB column[α]D25=-21.7 (c 7.0, CHCl3)Source of chirality: Bacillus pumilus Phe-C3 alcohol dehydrogenaseAbsolute configuration: (3S)

Ethyl (S)-4-bromo-3-hydroxybutyrateC6H11O3BrEe = 91.4% by chiral GC with a CP-Chirasil-Dex-CB column[α]D25=-10.9 (c 1.0, CHCl3)Source of chirality: Bacillus pumilus Phe-C3 alcohol dehydrogenaseAbsolute configuration: (3S)

Ethyl (S)-3-hydroxy-3-phenylpropionateC11H14O3Ee = 95.7% by chiral HPLC with a Chiralcel OB-H column[α]D25=-33.1 (c 1.0, CHCl3)Source of chirality: Bacillus pumilus Phe-C3 alcohol dehydrogenaseAbsolute configuration: (3S)

Ethyl (R)-4-cyano-3-hydroxybutyrateC7H11O3NEe = 97.0% by chiral GC with a CP-Chirasil-Dex-CB column[α]D25=-32.1 (c 1.0, CHCl3)Source of chirality: Bacillus pumilus Phe-C3 alcohol dehydrogenaseAbsolute configuration: (3R)

Ethyl (R)-4,4,4-trifluoro-3-hydroxybutyrateC6H9O3F3Ee = 90.2% by chiral GC with a CP-Chirasil-Dex-CB column[α]D25=+20.1 (c 1.0, CHCl3)Source of chirality: Bacillus pumilus Phe-C3 alcohol dehydrogenaseAbsolute configuration: (3R)

Ethyl (R)-2-hydroxy-propionateC5H10O3Ee = 94.1% by chiral GC with a CP-Chirasil-Dex-CB column[α]D25=+14.3 (c 1.0, CHCl3)Source of chirality: Bacillus pumilus Phe-C3 alcohol dehydrogenaseAbsolute configuration: (2R)

Ethyl (R)-α-hydroxybenzeneacetateC10H12O3Ee = 96.6% by chiral HPLC with a Chiralcel OB-H column[α]D25=-99.3 (c 1.0, CHCl3)Source of chirality: Bacillus pumilus Phe-C3 alcohol dehydrogenaseAbsolute configuration: (2R)

Ethyl (R)-2-hydroxy-4-phenylbutyrateC12H16O3Ee = 97.1% by chiral HPLC with a Chiralcel OB-H column[α]D25=-19.5 (c 1.0, CHCl3)Source of chirality: Bacillus pumilus Phe-C3 alcohol dehydrogenaseAbsolute configuration: (2R)