节点文献

BINOL衍生的Lewis acid-Lewis base双功能手性催化剂的设计合成及其在不对称催化中的应用

Design and Synthesis Novel Lewis Acid-Lewis Base Bifunctional Catalysts Derived from BINOLs and Imidazoles and Their Applications in Asymmetric Catalysis

【作者】 杨飞

【导师】 游劲松;

【作者基本信息】 四川大学 , 有机化学, 2006, 硕士

【摘要】 设计和发展高效不对称催化剂已成为当今有机化学的一个热门领域并受到极大的关注。通过对酶作用的机理研究表明,酶催化是由两个或多个活性中心协同作用的结果,从仿生模拟的理念出发,多功能催化剂设计原理比传统方法具有更多的优点。这种催化剂具有手性Lewis酸和Lewis碱两个催化中心可以同时活化亲核和亲电前体。Lewis酸碱联合催化剂通过协同活化两个或多个反应中心可以带来高的反应速度和极佳的立体化学选择性。 本论文主要研究室温条件下手性Lewis acid-Lewis base双功能催化剂催化的炔基锌对醛的不对称加成,扩展了BINOL/Ti(OiPr)4/Et2Zn体系,使之能够适用于官能化炔的反应。我们首次发现了催化量的NMI及其它碱性化合物可在室温条件下快速促进炔基锌中间体的生成,并将N-甲基咪唑(NMI)、Et2Zn、BINOL和Ti(OiPr)4体系用于催化各种官能化炔与各种取代醛的加成反应可获得高产率和高ee值(94%ee)。通过两者的协同催化作用可降低手性配体BINOL的用量(从传统的20%降低到10%)。 从酶模拟和多功能催化剂设计原理出发进一步设计合成了六个3,3’-咪唑及咪唑衍生物修饰的BINOL类手性双功能催化剂,这是首次以手性联二萘酚为骨架的咪唑类双功能配体的设计合成。将这些配体的过渡金属络合物用于不对称催化反应,考察了不同双功能配体的对映选择性差异性。通过比较发现3-单咪唑基取代的BINOL配体和Ti(OiPr)4组成的双功能催化体系对室温条件下炔基锌对醛的不对称加成反应以及醛的不对称硅氰化反应有着极好的催化活

【Abstract】 The design and development of new high-performance catalysts for applications in asymmetric catalysis is of ongoing interest in organic chemistry. The mechanism of action of many enzymes involves the cooperation of two or more reactive centres. It is considered that by imitating nature, the principle of multifunctional catalysis could offer many advantages over existing strategies. An effective enantioselective synthetic method based on a new concept of double catalytic activation has been developed, in which both electrophile and nucleophile precursors are activated by the use of catalytic amount of chiral Lewis acid and Lewis base, respectively. This method has been successfully applied to enantioselective synthesis. The synergistic activation by two or more reactive centers allows high reaction rates and excellent transfer of stereochemical information.In this thesis, we focused on the enantioselective alkynylzincs addition to aldehydes catalyzed by chiral Lewis acid-Lewis base bifunctional catalysts at ambient temperature, in order to extend the application of the BINOL / Ti(OiPr)4 / Et2Zn system to the reaction related with functional alkynes. We discovered that in the presence of N-methyl-imidazole (NMI), Et2Zn, BINOL and Ti(OiPr)4, various functional alkynes could add to a wide scope of aldehydes at room temperature in

  • 【网络出版投稿人】 四川大学
  • 【网络出版年期】2007年 03期
  • 【分类号】O643.36
  • 【被引频次】1
  • 【下载频次】544
节点文献中: