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4-位取代的L-脯氨酸衍生物手性催化剂的合成及其催化不对称直接Aldol反应

Synthesis of 4-substituted Chiral Organocatalysts Derived from L-prolines and the Catalytic Effects on the Asymmetric Direct Aldol Reaction

【作者】 浮绍东

【导师】 傅相锴;

【作者基本信息】 西南大学 , 有机化学, 2010, 硕士

【摘要】 近十年来,不对称有机催化得到了很大的发展,成为有机化学研究的一个新热点。在有机小分子催化剂催化的反应中,由于高效、选择性好以及不使用金属离子从而优于传统的有机合成方法。其中,Aldol反应做为一种最有效的合成C-C键的方法,能够生成在许多天然产物和药物里常见的β-羟基酮(醛)的结构模块等,从而在近年来受到了高度的关注。然而,有机小分子催化的不对称反应不像自然界中的酶催化反应一样,在温和的条件下可以在水相中反应,对映选择性的有机催化反应大都发生在有机溶剂里,例如DMSO、DMF以及添加水的混合溶剂里。总之,能够在水相中发生反应并且具有高的对映选择性的催化体系在现代化学里仍很有限,而发展这些高效的催化体系必将成为人们不断追寻的目标。在本论文中,我们设计合成了一系列4-位叔丁基二甲基硅烷基取代的脯氨酰胺类手性有机小分子催化剂,并用来催化环己酮与各种取代芳香醛的不对称直接Aldol反应。研究结果表明:化合物1b具有最好的催化性能。当在优化的条件下使用3mol%的催化剂催化环己酮与芳香醛的Aldol反应时,反应产物可以取得大于99%的产率,以及完美的非对映选择性和对映选择性,分别是>99:1和>99%。值得一提的是,反应是在添加了大量的水而没有添加任何添加剂于温和的反应条件(室温)下进行的。

【Abstract】 In the latest decade, asymmetric organocatalysis has become an important area of research in organic synthesis. Organocatalysts which are metal-free small organic molecules are able to function as efficient and selective catalysts making many organocatalytic reactions superior to those carried out using more conventional methods, and among these reactions, the aldol reaction which is recognized as one of the most powerful carbon-carbon bond-forming reactions in modern organic synthesis, creating the (3-hydroxy carbonyl structural unit found in many natural products and drugs, has received much attention in recent years.However, unlike enzymatic reactions in nature that occur in water, enantioselective organocatalytic processes have typically been carried out in organic solvents, such as DMSO, DMF, or in mixed aqueous organic solvent, under mild conditions. Therefore, highly efficient catalytic system, which gives high enantioselectivity for a broad range of substrates in water, is still limited and currently a sought-after goal in modern chemistry.In this dissertation, a new system of 4-tert-butyldimethylsiloxy substituted organocatalysts derived from N-prolylsulfonamide has been designed by our group and proved to be effective in catalyzing the direct aldol reactions of cyclic ketones with a series of aromatic aldehydes. The research showed that the best catalytic efficiency was observed with 1b. When 3 mol% of 1b was used to catalyze the reaction without using any additives in a large amount of water under mild conditions(at room temperature), the aldol products were obtained in very good yields (>99%) with excellent diastereoselectivities up to>99:1 and enantioselectivities up to>99%.

  • 【网络出版投稿人】 西南大学
  • 【网络出版年期】2010年 08期
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