The Study On The Synthesis And Application Of Chiral Dipeptide And Imidazoline

In this dissertation, we have designed and synthesized the imidazoline-phenol, pyrrolidine-imidazoline and dipeptide which composed the proline, three kinds of bifunctional catalysts and applied them to catalyze asymmetric reactions. Preliminary study indicated that the imidazoline-phenol catalyst with low reactivity and the pyrrolidine-imidazoline catalyst with good reactivity in the Aldol and Michael reaction, in order to get good results, we have also optimized the solvent, additive and found that the reactivity would be enhanced by adding TFA. In the same time, we also found that the Aldol products were obtained with high reactivity and selectivity catalyzed by the dipeptide which derived from proline. We have studied the influence of electronic effect and steric effect on the reaction by varied the structure of another amino acid and terminal amide of the dipeptide and found that the best catalyst was 48g, and use it in the direct asymmetric Aldol reation. The reaction temperatures, solvents and additives were screened and found that the proper temperature was -20℃, the best solvent was CHCl₃ and the additive was AcOH or 2-MePhCOOH. With the optimal conditions in hand, we investigated the reaction of cyclohexanone with various aldehydes, high isolated yields (up to 99%) and enantioselectities (up to 98% ee) were obtained.