Development of Asymmetric Catalysis of Synthetic Reactions

本工作的目的是开发一些C-C键形成反应的高效不对称催化。研究结果总结如下：(1)不对称醛醇反应的催化立体控制：利用Eu（III）配合物作为催化剂，手性α -氨基醛与烯酮硅基缩醛的醛醇反应实现了高水平的双立体控制，并将催化醛醇技术成功应用于碳青霉烯类抗生素和肾素抑制剂关键中间体的不对称合成。(2)羰基-烯反应的不对称催化：发现由旋光性双酚衍生的手性钛配合物可作为乙醛-烯反应的有效不对称催化剂，为高对映体过量的-羟基酯提供了实际途径。有趣的是，观察到“不对称放大”现象，并阐明了其机制起源。(3) diols - alder型反应的不对称催化作用：上述手性钛配合物可作为杂合d - a的不对称催化剂。与乙醛酸酯和d - a反应。与甲基丙烯醛和醌的反应。(4)烯丙基金属/醛加成反应的不对称催化：上述手性ti配合物也是烯丙基硅烷和锡烷与乙醛酸盐加成反应的有效不对称催化剂。(5)不对称催化clisen重排：钯配合物通过醚交换过程对clisen重排具有有效的非对映选择性催化作用。然而，不对称催化剂的开发仍未取得成功。进一步的工作正在进行中。

The purpose of this work is to develop efficient asymmetric catalysis of some C-C bond forming reactions. A summary of the research results is as follow: (1) Catalytic Stereocontrol in Asymmetric Aldol reactions : Using Eu(III)-complexes as a catalyst, high levels of distereocontrol have been achieved in the aldol reactions of chiral alpha-amino aldehydes with ketene silyl acetals Furthermore, the catalytic aldol technology has successfully been applied to asymmetric synthesis of the key intermiediates of carbapenem antibiotics and renin inhibitors. (2) Asymmetric catalysis of Carbonyl-Ene Reactions : The chiral titanium complex derived from optically active binaphthol was found to serve as an efficient asymmetric catalyst for glyoxylate-ene reaction to provide a practical access to alpha-hydroxy esters in high enantiomeric excess. Interestingly, the phenomenon of "asymmetric amplification" was observed and its mechanistic origin was elucidated. (3) Asymmetric Catalysis of Diels-Alder Type Reactions : The above-mentioned chiral titanium comples was found to serve as an asymmetric catalyst for hetero D.-A. reaction with the glyoxylate and D.-A.reactions with methacrolein and quinones. (4) Asymmetric Catalysis of Allylmetal/Aldehyde Addition Reactions : The abovementioned chiral Ti-complex was also found to be an efficient asymmetric catalyst for the addition reactions of allylic silanes and stannanes to the glyoxylate. (5) Asymmetric Catalysis of Claisen Rearrangement : A palladium (II) complex was found to show an efficient and diastereoselective catalysis of the Claisen rearrangement via an ether exchange process. However, the development of an asymmetric catalyst has been still unsuccessful. Further work is in progress.