Novel chiral imidazole cyclophane receptors were synthesized by highly selective N-alkylation of the imidazolyl 1Nposition of the bridged histidine diester 2 with the dibromide in the presence of NaH; these receptors exhibit good chiral recognition toward the enantiomers of L-and D-amino acid derivatives (up to KD/KL=3.52, △△G0=-23.11 kJ mol-1) in CHCl3 at 25.0℃.

The asymmetric addition of Me3SiCN to aldehydes catalyzed by titanium (IV) complexes of N-sulfonylated derivatives of b-amino alcohols gave excellent ee's up to 96% ee.

In the presence of a catalytic amount of a simple copper salt, the coupling of imidazole with arylboronic acids was performed in methanol to give corresponding N-arylimidazoles in almost quantitative yields; this coupling reaction could also be performed in aqueous solutions to give N-arylimidazoles in excellent yields.

The asymmetric methylation, ethylation and allylation of aldehydes using trialkylaluminium reagents catalyzed by titanium (IV) complexes of N-sulfonylated amino alcohols gave excellent enantioselectivities of up to 99% ee.

The enantioselective hydrogenation of E- and Z-methyl 3-acetamidobutenoate, key intermediates in the synthesis of a pharmaceutically important chiral β-amino acid, with RhI catalysts in MeOH as solvent has been investigated in detail. As chiral ligands, Et-DuPHOS, Me4-BASPHOS, DIPAMP, DIOP, HO-DIOP and Et-Ferro-TANE have been employed. T he particular role of oxyfunctionalization in some diphosphine catalysts is addressed in relation to the E/Z geometry of the substrate and the dependency of the ee on the H2 pressure.Kinetic investigations with [Rh (diphosphane) (MeOH) 2]-BF4, taking into consideration the special nature of the precatalyst {[Rh-(cod) 2] BF4/ligand versus [Rh (cod) ligand)] BF4}, NMR spectroscopic measurements and the H2 pressure dependence of the observed enantioselectivity provide evidence that the reaction proceeds via an "unsaturated route" mechanism. T his mechanism correlates to catalytic features found in the past for the hydrogenation of related unsaturated-amino acid precursors. T he influence of the temperature was similarly investigated.A nonlinear dependency of the enantiomeric ratio as a function of the reciprocal of the temperature has been found. The correlation between temperature and H2 pressure and their effects on the enantioselectivity is discussed. In general, the highest enantioselectivities for the hydrogenation of both isomeric substrates can be achieved at room temperature and below, whereas the fastest conversion takes place at 30-50℃.