1210
P. Hildebrandt et al. / Tetrahedron: Asymmetry 12 (2001) 1207–1210
phenylethanol 4a, 5.61 min, (S)-4a, 5.86 min; 4-fluoro-
acetophenone 6, 1.58 min, (R)-fluoro-a-phenylethanol
6a, 3.03 min, (S)-6a, 3.28 min; 90°C for 1 min, heating
at 5°C/min to 120°C, retention times: 4-chloro-ace-
tophenone 7, 3.62 min, (R)-4-chloro-a-phenylethanol
7a, 5.52 min, (S)-7a, 5.90 min; 4-methyl-acetophenone
2, 2.63 min, (R)-4-methyl-a-phenylethanol 2a, 3.40 min,
(S)-2a, 3.76 min; 4-methoxy-acetophenone 5, 4.94 min,
(R)-4-methoxy-a-phenylethanol 5a, 5.52 min, (S)-5a,
5.74 min; 70°C isothermal: 3-oxobutyric acid
methylester 8, 2.20 min, (R)-3-hydroxybutyric acid
methylester 8a, 3.84 min, (S)-8a, 3.99 min. Absolute
configurations were assigned for 1a and 8a using com-
mercially available (R)-alcohols and for 2a–7a by
assuming the same elution order as determined for 1a.
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Acetophenone 1 (200 mg, 50 mM) was dissolved in
iso-propanol (6.58 mL) and Tris–HCl (0.1 M, pH 8.0,
26.52 mL). The reaction was started by addition of
lyophilized crude cell extract (320 mg). Due to the
moderate stability of the enzyme, further addition of
crude PFADH (final amount: 2 g) was necessary until
73.5% conversion was achieved. After work-up of the
reaction mixture as described above, (R)-a-
phenylethanol was isolated in 63% yield (e.e.=92%).
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Acknowledgements
Financial support from Aventis Research and Tech-
nologies GmbH (Frankfurt, Germany) is gratefully
acknowledged. We also thank Markus Durban for his
assistance during his practical course.
18. Malone, V. F.; Chastain, A. J.; Ohlsson, J. T.; Poneleit,
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