| abstract |
Compounds of the forulae I and Ia <IMAGE> (I) and <IMAGE> (Ia) in which R1 is a group which can be transferred to carbonyl or imine compounds, for example alkyl, allyl, vinyl or the radical of an enol or enamine, R2 is, for example, cyclopentadienyl, R3 is the radical of an optically active sugar or sugar derivative, Me is Ti, Zr or Hf, x is 0, 1 or 2 and y is 0, 1, 2 or 3, M(+) is Li(+), Na(+), K(+), MgY(+), ZnY(+), CdY(+), HgY, CuY(+) or quaternary ammonium, Y being halogen, are suitable for use as chiral reactants for compounds containing aldehyde, keto and/or N-substituted imine groups. |