| abstract |
The present invention relates to a process for preparing (S) or (R) -4-halo-3-hydroxybutyrate, comprising reacting 4-haloacetoacetate with hydrogen in the presence of a solvent, Comprises a first solvent and a second solvent, the first solvent is an aliphatic alcohol, preferably methanol, ethanol or propanol, the second solvent is aprotic and contains at least one oxygen atom, the catalyst is of the formula [RuXYZ] X, X is halogen, preferably Cl or Br, or OAc, acetoacetate, allyl or ClO 4 , Y is a bidentate organic ligand having two phosphine groups, Z is an arene, preferably cymene, benzene, xylene Or toluene, or polyene, preferably diene, or alkene. |