4-位取代的L-脯氨酸类手性催化剂的合成及其β-环糊精包合物的制备

【作者】 毛宇鸿；

【导师】 王伟；

【作者基本信息】 陕西师范大学 ， 有机化学， 2011， 硕士

【摘要】 不对称合成特别是以有机小分子催化的不对称合成方法学及其应用吸引了众多化学科研者的注意,目前己在合成领域占有重要地位。同时,其催化的多数反应能够得到比较理想的收率和立体选择性。脯氨酸是应用比较成功和广泛的有机小分子催化剂,但是它在某些方面还存在缺点。因此,人们设计合成出了多种脯氨酸的衍生物包括有脯氨酰胺类、脯氨醇类以及4-位取代的L-脯氨酸类等,期望能够改善其在有机溶剂中的溶解度,同时得到较高的收率和较好的立体选择性。本论文主要设计合成了几种4-位取代的L-脯氨酸类衍生物,以Boc-反式-4-羟基脯氨酸为原料,通过威廉逊醚化法,去Boc保护,得到目标产物,并以其中的两种衍生物与β-CD通过包合作用形成固载催化剂。目标产物的结构分别通过红外光谱、1HNMR、13CNMR、X-射线粉末衍射表征和确认。本论文主要包括以下四部分内容：第一章：首先,对脯氨酸及其衍生物的种类做了全面的综述,同时简述了其催化的不对称反应的收率和立体选择性。其次,对目前固载化脯氨酸及其衍生物的载体种类及其催化不对称反应的收率和立体选择性也做了简单的介绍。第二章：通过自由基反应合成了几种苄位的溴化试剂。通过实验结果显示该反应最终产物受温度和溶剂的影响。同时,苯环上的取代基对反应的转化率也有一定的影响,当取代基为吸电子基团时(-COOH,-Br),反应彻底,转化率高；当取代基为供电子基团时(-OCH3),反应原料始终有剩余,转化率较低。第三章：首先以Boc-反式-4-羟基脯氨酸甲酯为原料,在NaHH作用下与溴化苄发生醚化反应,再经去保护合成(4R)-苄氧基-(2S)-脯氨酸和(4S)-苄氧基-(2S)-脯氨酸。在此基础上,以Boc-反式-4-羟基脯氨酸为原料,通过同样的方法继续合成了4种4-位取代的L-脯氨酸类衍生物。根据实验现象和结果显示,苯环上的取代基对反应有很大影响。其中,当苯环上没有取代基时,反应在室温下就可以发生,并且反应后处理简单,表现在与烯丙基溴和溴化苄的反应上当苯环上连有取代基时,反应第一步原料始终有剩余,增加了反应后处理的复杂性,而且取代基的不同使反应发生的难易程度也不同,表现为取代基为强的吸电子基团如硝基、羧基时,反应很难发生；取代基为供电子基团或弱的吸电子基团如甲基、甲氧基、溴时,反应相对于前者容易得多。第四章：通过溶液搅拌法制备了两种脯氨酸衍生物与β-环糊精的包合物,包合物经红外光谱和X-射线粉末衍射表征,证实发生了包合作用。最后对全文进行了总结。更多还原

【Abstract】 A large number of chemical researchers are favored of the methodology and application of the asymmetric synthesis especially catalyzed by organocatalisis. At the same time, organocatalisis have played an important role in the fields of the synthesis and most of the reactions which were catalytyzed by organocatalisis can get much higher yield and good stereoselectivity.Proline is the most successful and widespread using of the organocatalysis but in some areas there are still shortcomings. Thus, a variety derivatives of proline were designed. For example, there are the prolinamide, prolinamide alcohol and the 4-substituted L-proline derivatives. All of them were synthesized in order to improve the solubility in organic solvents and get much higher yield and good stereoselectivity. This paper prepared several 4-substituted L-proline derivatives hoping to improve its solubility in organic solvents and also get good stereoselectivity. We start the Boc-trans-4-hydroxyproline as raw material to take place the William son and then remove the protection of Boc to synthesis several 4-substituted L-proline derivatives. Two of them were conformed inclusion complex withβ-CD. The structure’s of the target products were characterized by IR.1HNMR,13CNMR and XRD.This thesis consists of four chapters:In chapter one:Firstly, give a full review of the types of proline and its derivatives about yield and stereoselectivity in catalyticing asymmetric reaction.Secondly, make a brief introduction of the present immobilization carrier of proline and its derivatives in catalyticing asymmetric reactions’ types being included yield and stereoselectivity.In chapter two:several benzyl bromide reagents were synthesised by radical reactions.lt is found that the reaction can get different products in different solvents and tempreture. The substituents of benzene conversion is another factor. When the substituent group is electron withdrawing(-COOH,-Br), the reaction can be completed and highly conversed rate while when the substituent is the electron group(-OCH3), the raw materials always has a surplus and lowly conversed rate.In chapter three:Firstly, taking the Boc-trans-4-hydroxy-prolinemethylester as raw materia reacted with benzyl bromide under NaH then removing the protection to get (4R)-benzyloxy-(2S)-proline and (4S)-benzyloxy-(2S)-proline. On the basis of the former work, we also synthesize four 4-substituted L-proline derivatives by the same method instead of the Boc-trans-4-hydroxy-proline as the start material.We found that the different substituents of the benzene ring had a great influence on the reaction accrossing the experimental phenomena and results. When there is no substituent on the benzene ring, the reaction can occur at room temperature and the post-processing is simple. The reaction of allyl bromide and benzyl bromide are the good examples. While with a substituent the first step of the reaction always have the residual material leading to the complexity of the treatment of the reaction and the different substituents have different degrees of difficulty. If the substituent is the strong electron-withdrawing group such as -NO2,-COOH, the reaction is difficult to occur while the substituent is the electron-donating or weak electron-withdrawing group such as -CH3,-OCH3,-Br, the reaction is much easier compared to the former.In chapter four:Two inclusion complexes of the 4-substituted L-prolines’derivatives andβ-cyclodextrin were prepared by mixing solution.The inclusion was confirmed by the IR and XRD.Finally, the text is summarized.更多还原