【作者】 郑欣；

【导师】 王永梅；

【作者基本信息】 南开大学 ， 有机化学， 2010， 硕士

【摘要】 不对称有机小分子催化已经成为不对称合成领域至关重要的组成部分。小分子催化所实现的全新的底物活化方式给人们提供了除过渡金属催化剂外的更多的选择。脯氨酸作为一种结构简单、商品化的、廉价手性小分子催化剂,在多种不对称催化反应中表现出非常好的催化性能。脯氨酸的广泛应用将不对称的有机小分子催化带入了一个崭新的时代。近年来,离子液体作为一种绿色的介质,既可以作反应的溶剂又可以做催化剂,是近年来有机合成的新兴研究的热点之一。它具有不挥发性,不易燃性,热稳定性,极高的离子导电性,对与绝大多数有机和无机化合物有较好的溶解性,用离子液体作溶剂或催化剂具有反应速度快、产物后处理方便、而且催化剂离子液体易于回收。在各种各样的离子液体中,手性离子液体无疑是离子液体研究的焦点,因为它兼具溶剂和手性催化剂的双重特性,在不对称有机合成中有很大的应用潜力。手性氨基酸离子液体根据氨基酸主体在离子液体中的位置不同,可以分为氨基酸修饰的阳离子手性离子液体和氨基酸修饰的阴离子手性离子液体。以氨基酸修饰的阳离子手性离子液体为催化剂的研究已经受到化学家的广泛关注,但基于阴离子修饰的手性氨基酸离子液体用作催化剂还未见报道。因此,我们首次以脯氨酸为手性阴离子的离子液体[EMIm][Pro]为催化剂,用于Mannich反应、Diels-Alder反应和Aldol反应的不对称催化合成之中。通过对反应溶剂、温度、催化剂用量等条件的优化,我们可以得到高立体选择性的目标产物。该离子液体催化的Diels-Alder反应和Aldol反应可以循环使用多于四次,绿色环保,减少了有机溶剂的使用,符合绿色化学的原子经济性原则。更多还原

【Abstract】 Organocatalysis has become a field of central importance for the asymmetric synthesis of chiral molecules. Novel modes of substrate activation have been achieved using organocatalysts that can now deliver unique, orthogonal, or complementary selectivities comparable to many established metal-catalyzed transformations. Notably, proline has been gradually recognized as a simple, commercial and cheap chiral catalyst for many asymmetric organic reactions. The use of simple proline as catalyst for asymmetric organic reactions at the beginning of this century became a milestone in the growth of organocatalysis as a useful synthetic strategy.In the recent years, ionic liquids are attracting considerable attention as reaction solvents and catalysts for their remarkable properties, including a negligibly small vapor pressure, high thermal stability, immiscibility with most organic/inorganic solvents, high ionic conductivity and easily recovered by careful washing in ether or pentane.Among the various ionic liquids, chiral ionic liquids are particularly attractive and important for their widespread potential applications in asymmetric synthesis. Some derived from natural amino acids, which have shown to serve as effective catalysts. Amino acid ionic liquids have mostly been designed using a series of cationic derivatives due to their convenient chemical modification, but there is much less information about the effect of anion structure.Therefore, we first employed proline anion as an effective module with ionic liquid for the asymmetric Mannich reaction, Diels-Alder reaction and Aldol reaction. Different solvents, reaction temperatures and the ratio of catalyst were investigated in these reactions. Under optimal conditions, high enantio-and diastereoselectivities compounds have been achieved. Most importantly, regarding to atom economy and green chemistry, this efficient system can be reused more than 4 runs in Diels-Alder reaction and Aldol reaction.更多还原