DIRECT CONVERSION OF (1S,2S)-2-AMINO-1-[(4-METHYLTHIO)PHENYL]-1,3-PROPANEDIOL INTO ITS ENANTIOMER FOR EFFICIENT SYNTHESIS OF THIAMPHENICOL AND FLORFENICOL

The usual synthesis of thiamphenicol and florfenicol involves the resolution of racemic threo-2-amino-1-[(4-methylthio)phenyl]-1,3-propanediol into its 1S,2S and 1R,2R isomers ((+)-3 and (-)-3), of which only the latter is a useful precursor. An efficient conversion of the 1S,2S isomer into the 1R,2R enantiomer in high yield, is described.