INVESTIGATION OF THE INFLUENCE OF CARBOHYDRATE AMPHIPHILES ON THE COMPLEX-CATALYZED ASYMMETRIC HYDROGENATION OF (Z)-METHYL ALPHA-ACETAMIDOCINNAMATE IN WATER

A series of carbohydrate amphiphiles has been tested in the asymmetric hydrogenation of (Z)-methyl alpha-acetamidocinnamate using water as m edium. Dependent on the chain length and the hydrophilicity of the hea d group an enhancement of activity and enantioselectivity of the [Rh(C OD)(2)]BF4 + BPPM catalyst system could be observed. Sometimes the ena ntioselectivity exceeds that in methanol. The method used here is conv enient and environmentally friendly because carbohydrates as amphiphil es are biologically degradable in water, Selected carbohydrate amphiph iles are able to transfer chirality onto the included substrate in a l ow manner (up to 6% ee). In these cases hydrogen bondings in the head group seem to be responsible for the effect of chiral induction.