Regio- and enantioselective reduction of diketones: preparation of enantiomerically pure hydroxy ketones catalysed by Candida parapsilosis ATCC 7330

Enantiomerically enriched hydroxy ketones were prepared by the reduction of the corresponding diketones with excellent enantiomeric excess (98%) and in good yields (up to 75%) using whole cells of Candida parapsilosis ATCC 7330. Cyclic diketones, such as 1,2-cyclohexanedione and 1,4-cyclohexanedione, resulted in hydroxy ketones as products. Cyclohexane-1,3-dione and 5,5-dimethylcyclohexane-1,3-dione gave dimerised products, such as 2,2′-(ethane-1,1-diyl)bis(3-hydroxycyclohex-2-enone) and 2,2′-(ethane-1,1-diyl)bis(3-hydroxy-5,5-dimethylcyclohex-2-enone) with acetaldehyde generated in situ from whole cells of Candida parapsilosis ATCC 7330, which is reported here for the first time.

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(S)-2-Hydroxy-1,2-diphenylethanoneC14H12O2ee = 98%[α]D25 = +71.2 (c 0.25, acetone)Source of chirality: Biocatalytic asymmetric reductionAbsolute configuration: (S)

(S)-2-Hydroxy-1-phenylpropan-1-oneC9H10O2ee = 98%[α]D25 = −82.4 (c 2, CHCl3)Source of chirality: Biocatalytic asymmetric reductionAbsolute configuration: (S)

(S)-2-Hydroxy-1-phenylbutan-1-oneC10H12O2ee = 36%[α]D25 = −11.2 (c 1, CHCl3)Source of chirality: Biocatalytic asymmetric reductionAbsolute configuration: (S)

(S)-2-HydroxycyclohexanoneC6H10O2ee = 69%[α]D25 = −10.2 (c 0.5, CHCl3)Source of chirality: Biocatalytic asymmetric reductionAbsolute configuration: (S)

(R)-3-Hydroxy-1-phenylbutan-1-oneC10H12O2ee = 92%[α]D25 = −48.5 (c 1, CHCl3)Source of chirality: Biocatalytic asymmetric reductionAbsolute configuration: (R)

(R)-4-Hydroxypentan-2-oneC5H10O2ee = 85%[α]D25 = −54.5 (c 2, CHCl3)Source of chirality: Biocatalytic asymmetric reductionAbsolute configuration: (R)