不对称Reformatsky反应的研究

分别将催化计量和化学计量的(1R, 2S)或(1S, 2R)-2-氨基-1,2-二苯基乙醇衍生的手性氨基醇配体1应用于催化不对称Reformatsky反应, 研究了手性配体的结构及其用量与反应对映选择性的关系, 溶剂和底物改变对e.e.值的影响; 并设计与研究了双手性体系, 使该反应在催化量(25mol%)手性配体的作用下, 得到中等对映选择性; 另外, 还比较了不同的实验方法对反应的对映选择性的影响, 提出了手性催化循环机理和反应过渡态模型, 能较好地解释一系列实验事实。

Study on asymmetric reformatsky reaction

A series of derivatives of (1R ,2S) or (1S ,2R) - 2 - amino - 1,2 - diphenyl ethanol (1) have been applied to asymmetric Reformatsky reaction of benzaldehyde (2) with alkyl bromoacetate (3). The influence of structure of the chiral aminoalcohol on the enantioselectivity was studied. Then several reaction parameters were also researched,including the amount of chiral ligand,solvent effect and alternation of the substrate. Furthermore, 0. 25 mol % of the chiral ligands were employed in the reaction of benzaldehyde with optically active menthyl bromoacetate and moderate enantioselectivity has been achieved via matched double chiral induction. The effect of various experimental methods on the enantioselectivity was also studied. Finally, a catalytic asymmetric mechanism was suggested. Moreover, the most experimental facts can be explained by the mechanism proposed.