Microbial reduction with baker's yeast or Apergillus niger of methyl 4-chloro-4,4-difluoro-3-oxobutanoate afforded the optically active (-) methyl 4-chloro-4,4-difluoro-3-hydroxybutanoate. When the yeast reduction was carried out in the presence of allyl bromide the optically active (+) hydroxyester was obtained. Treatment of the (-)enantiomer with methylamine afforded the corresponding solid amide having (S) absolute configuration, as displayed by single crystal X-ray diffraction analysis.
Microbial Synthesis and Absolute Configuration of Methyl (+) and (-) 4-Chloro-4,4-difluoro-3-hydroxybutanoate / Antolini, Luciano; Forni, Arrigo; Moretti, Irene; Prati, Fabio; Torre, Giovanni. - In: GAZZETTA CHIMICA ITALIANA. - ISSN 0016-5603. - STAMPA. - 125:(1995), pp. 549-553.