Microbial Synthesis of Methyl (+) and (-) 4-Chloro-4,4-difluoro-3- hydroxybutanoate

Microbial reduction with baker's yeast or Aspergillus niger of methyl 4-chloro-4,4-difluoro-3-oxobutanoate 1 afforded the optically active methyl (-)-4-chloro-4,4-difluoro-3-hydroxybutanoate 2. When yeast reduction was carried out in the presence of allyl bromide, optically active (+)-2 was obtanied.