PROCESS FOR PREPARATION OF (S)- OR (R)-4-halo-3-HYDROXYBUTYRATE

摘要

PROBLEM TO BE SOLVED: To provide a process for the preparation of enantiomerically pure (S)- or (R)-4-halo-3-hydroxybutyrates.SOLUTION: A 4-halo-3-hydroxybutyrates shown by formula (S)-I or (R)-I are obtained by asymmetric hydrogenation of a 4-halo-3-oxobutyric acid esters in the presence of a catalyst of a ruthenium complex comprising a chiral ligand. In the formula, Ris CHX, CHXor CXand X independently represents Cl and/or Br; Ris C-alkyl, C-cycloalkyl, aryl or aralkyl, each aryl or aralkyl being optionally further replaced with one or more C-alkyl groups and/or halogen atoms.