Novel unusual microbial dehalogenation during enantioselective reduction of ethyl 4,4,4-trifluoro acetoacetate with bakerʹs yeast

In the course of investigating microbial syntheses for chiral pharmaceutical intermediates, ethyl 4,4,4-trifluoro acetoacetate (1) was submitted to bakerʹs yeast reduction. With the purpose of obtaining the d-carbinol in high enantiopurity, several additives were tested for l-reductase inhibitor activity. Allyl alcohol proved to be not only a suitable additive, but also an inducer for effective defluorination of the substrate.