【作者】 李蕾蕾；

【导师】 谢如刚；

【作者基本信息】 四川大学 ， 有机化学， 2003， 硕士

【摘要】 不对称合成与催化是当今有机化学的前沿领域之一。探索与开发具有高效性与高选择性的合成反应是当今合成化学研究的热点问题。本文设计了两条路线来合成一系列以1，2-二苯基乙二胺为桥联基团的双方酰化氨基酸配体。将其应用于前手性单酮及二酮的还原中，其中双方酰化脯氨酸在1，6-二苯基-1，6-己二酮的还原反应中可获得最高为90％的ee值。 本文考察了由L-半胱氨酸衍生的2-位无取代基的以及2-位芳基取代的噻唑烷酸及醇配体在前手性酮的不对称还原反应中的催化性能。其中无取代基的噻唑烷酸配体及其相应的醇配体得到的手性仲醇的ee值分别最高可达到99％和94％；而C-2位芳基取代的噻唑烷酸及醇配体的催化性能则略差。我们发现这两类配体催化前手性酮得到的产物醇具有相反的构型，其中前者所得的产物醇构型与著名的CBS催化剂所得结果相同，后者则与CBS催化剂得到的结果相反。本文对催化机理进行了探讨，并提出了可能的反应历程。 C-2位取代的噻唑烷酸及醇配体具有两个手性中心，且C-2位的手性中心很可能对催化结果存在着一定的影响。本文合成了(2S，4R)和(2R，4R)型的N-Boc噻唑烷酸以及它们相应的醇配体，其中，(2S，4R)型的噻唑烷酸已通过单晶X-Ray衍射分析确定了其绝对构型。更多还原

【Abstract】 Asymmetric synthesis and catalysis is a hot field in morden organic chemistry. Exploration of high effective and enantioselective synthesis is a highlight in moden synthesis chemistry. In this paper, we designed two routes to synthesize a series of bis-squaramidoacid ligands bridged by 1,2-diphenylethylenediamine. Then we applied these chrial ligands to asymmetric borane reduction of w-bromoacetophenone and diketones. In the reduction of 1, 6-diphenyl-1, 6-hexanedione catalyzed by the bis-squaryl proline, good enantioselectivities were obtained, the ee values were up to 90%.We also studied the asymmetric borane reduction of prochiral ketone catalyzed by a series of thiazolidine ligands. In the reduction of w-bromoacetophenone, the thiazolidinecarboxylic acid and thiazolidine methanol ligand without substituent on C-2 position showed excellent enantioselectivities, the ee values were up to 99% and 94% respectively. The thiazolidine ligands with aromatic substituents on C-2 position provided relatively poor enantioselectivity. We also found that these two kinds of ligands afforded the alcohol product with opposite configuration, and the thiazolidine ligands with aromatic substituents on C-2 position showed opposite enantioselectivity related to CBS catalyst derived fromL-prolinols. We investigated the asymmetric reduction process and supposed a mechanism of the reaction.The C-2 substituted thiazolidinecarboxylic acids have two chiral centers, and the configuration on C-2 position may affect the enantioselectivity of the reduction. We synthesized (2S, 4R) and (2R, 4R)-2-phenyl-3- (tert-butoxycarbonyl) thiazolidine-4-carboxylic acids and their corresponding alcohol ligands. Crystal structure of (2R, 4R)-2 -phenyl- 3 - (tert-butoxycarbonyl) thiazolidine- 4 -carboxylic acid was confirmed by X-ray analysis.更多还原