Deracemization of 1-phenylethanol via tandem biocatalytic oxidation and reduction

(R)-1-Arylethanols and other secondary alcohols were prepared at high ee (>90%) by oxidative kinetic resolution using resting cells of the yeast Candida albicans CCT 0776. The deracemization process of 1-phenylethanol 1a catalyzed by the yeast was elucidated by studying each step separately. It was determined that the reaction occurred via cyclic deracemization, to give (R)-1a in 89% yield and with 98% ee. Finally, deracemization by stereoinversion of rac-1a was studied using a tandem process of C. albicans followed by Lactobacillus brevis CCT 3745. Inverting the sequence of these microorganisms produced an enantiomerically pure antipode.

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(R)-1-PhenylethanolC8H10Oee = 99%[α]D20=+55 (c 1.0, CHCl3)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)

(R)-1-(4-Chlorophenyl)-ethanolC8H10ClOee = 87%[α]D20=+50 (c 0.5, CHCl3)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)

(R)-1-(4-Fluorophenyl)-ethanolC8H10FOee = 99%[α]D20=+26 (c 3.2, CH2Cl2)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)

(R)-1-(4-Bromophenyl)-ethanolC8H10BrOee = 99%[α]D20=+26 (c 1.1, CHCl3)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)

(R)-1-(4-Hydroxyphenyl)-ethanolC8H10O2ee = 99%[α]D20=+29 (c 3.4, ethanol)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)

(R)-1-(4-Methylphenyl)-ethanolC9H12Oee = 99%[α]D20=+53 (c 0.4, CHCl3)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)

(R)-1-(4-Methoxyphenyl)-ethanolC9H12O2ee = 99%[α]D20=+43 (c 0.5, CHCl3)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)

(R)-1-(3-Hydroxyphenyl)-ethanolC8H10O2ee = 99%[α]D20=+32 (c 1.0, MeOH)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)

(R)-1-(3-Methoxyphenyl)-ethanolC9H12O2ee = 99%[α]D20=+28 (c 1.0, CHCl3)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)

(R)-2,3-Dihydro-1H-inden-1-olC9H10Oee = 99%[α]D20=-21 (c 1.0, CHCl3)Source of chirality: Asymmetric synthesisAbsolute configuration: (R)