Preparation of enantiomerically pure (3E)-alkyl-4-(hetero-2-yl)-2-hydroxybut-3-enoates by Candida parapsilosis ATCC 7330 mediated deracemisation and determination of the absolute configuration of (3E)-ethyl-4-(thiophene-2-yl)-2-hydroxybut-3-enoate

Deracemisation of racemic (3E)-alkyl-4-(hetero-2-yl)-2-hydroxybut-3-enoates using Candida parapsilosis ATCC 7330 resulted in the formation of one enantiomer in high enantiomeric excess [up to >99% ee] and isolated yields [up to 79%]. The absolute configuration of the enantiomerically pure (3E)-ethyl-4-(thiophene-2-yl)-2-hydroxybut-3-enoate as determined by 1H NMR of the Mosher esters was found to be (S).

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(3E)-Ethyl-4-(thiophen-2-yl)-2-hydroxybut-3-enoateC10H12O3SEe >99%[α]D25=+97.6 (c 1, MeOH) (rotation for corresponding acid)Source of chirality: biocatalytic deracemisationAbsolute configuration: (S)

(3E)-Methyl-4-(thiophen-2-yl)-2-hydroxybut-3-enoateC9H10O3SEe >99%[α]D25=+96.9 (c 1, MeOH) (rotation for corresponding acid)Source of chirality: biocatalytic deracemisationAbsolute configuration: (S)

(3E)-Ethyl-4-(furan-2-yl)-2-hydroxybut-3-enoateC10H12O4Ee >99%[α]D25=+25.6 (c 1, MeOH) (rotation for corresponding acid)Source of chirality: biocatalytic deracemisationAbsolute configuration: (S)

(3E)-Methyl-4-(furan-2-yl)-2-hydroxybut-3-enoateC9H10O4Ee >99%[α]D25=+25.1 (c 1, MeOH) (rotation for corresponding acid)Source of chirality: biocatalytic deracemisationAbsolute configuration: (S)