TRIFLUOROMETHYL VS. METHYL ABILITY TO DIRECT ENANTIOSELECTION IN MICROBIAL REDUCTION OF CARBONYL SUBSTRATES

The stereoselective reduction of 3-trifluoromethylcyclohexanone (1a), (E)-1.1.1-trifluoro-4-phenyl-3-buten-2-one (3a). and their unfluorinat ed analogues 1b and 3b has been performed with some growing microorgan isms. Differences in tile electronic and steric properties of tile tri fluoromethyl and methyl residues result in different chemo- and stereo selectivities in the microbial reduction of phenylbutenones 3a and 3b while cyclohexanones 1a and 1b showed strictly similar stereoselectivi ties. A new protocol based on C-13 NMR spectra of 2-phenylpropionic ac id esters has been used to assign tile absolute configuration of the o btained secondary alcohols. (C) 1998 Elsevier Science Ltd. All rights reserved.