Biocatalytic Preparation of (R)-(−)-4-(Phenylthio)-2-butanol and (R)-(−)-4-(Phenylsulfonyl)-2-butanol by the Sequential Use of Pichia farinosa and Rhodococcus rhodochrous

Preparation of (R)-4-(phenylthio)-2-butanol and (R)-4-(phenylsulfonyl)-2-butanol has been established based on the sequential use of two biocatalysts. A Pichia farinosa IAM 4682 mediated reduction of 4-(phenylthio)-2-butanone afforded (R)-4-(phenylthio)-2-butanol (91%e.e.) in 90% yield. Contaminating (S)-enantiomer in the resulting product was selectively oxidized by Rhodococcus rhodochrous IFO15564 to leave pure (R)-enantiomer in 87% yield. From this product, highly enantiomerically pure (R)-4-(phenylsulfonyl)-2-butanol was obtained by hydrogen peroxide oxidation.