铀配位的多吡啶基单手性螺旋聚醚的合成及不对称催化性能研究

The catalysis of uranium compounds has been widely concerned. Single-handed helix is a chiral structure with chiral recognizing ability, has been widely applied not only to High Performance Liquid Chromatography （HPLC） chiral stationary phases, but also to asymmetric catalysis, such as poly(methacrylate)s and ramification. When they are used as chiral packing materials for HPLC, the polymer is known to slowly decompose and lose its helical structure by reaction with methanol. In our research, the project is a combination of uranium and a single-handed helical polyether. Firstly, a series of novel epoxide monomer with polypyridyl pendants (such as 3-(5-alkyl-cyclopenta[1,2-b:5,4-b']dipyridyl)-1,2-propylene oxide) need to be synthesized, and the synthesis method of high e.e. value epoxide will be explored. Then, the helical polyethers can be given by anionic ring-opening polymerization, and the helix will be evaluated the chiral recognizing ability. The polyethers have not methanolysis reaction and keep a stable single-handed helical conformation. Secondly, the soluble single-handed polyethers with polypyridyl pendants may be promising ligands in inner-tansition metal (Uranium) catalysis for a number of asymmetric reactions, such as asymmetric Michanl addition reaction and asymmetric allylation of benzaldehyde. The complexes of the single-handed helical polyethers with polypyridyl pendants and uranium, can expend the application research of uranium, and provide an entry point for research on asymmetric catalysis. This multi-pyridyl single-handed helical polyether coordinated to Uranium is expected to become a new functional material.

铀配合物催化剂由于其优良的催化性能而被广泛关注。手性螺旋聚合物（如聚丙烯酸酯类）及其金属配位衍生物因具有手性识别能力而可用作高效液相色谱的手性固定相及不对称反应的催化剂。本项目拟研究以铀与含多吡啶基的单手性螺旋聚醚为基础的不对称催化反应。首先，合成多吡啶基取代的新型手性环氧单体，即手性3-(5-烃基环戊二烯并[1,2-b:5,4-b']二吡啶基)-1,2-环氧丙烷，通过阴离子开环聚合制备单手性螺旋聚醚，从根本上解决螺旋聚丙烯酸酯类易溶剂解的问题。然后，通过多吡啶基上相邻的双氮原子与铀配位，制备新型的铀-聚醚类催化剂，研究其对Michanl加成、苯甲醛的烯丙化等反应的不对称催化作用。这种多吡啶基的单手性螺旋聚醚的铀配合物，能够拓展铀的应用研究领域，为不对称催化研究提供新的切入点，有望成为一种新型功能材料。

项目背景：.单手性螺旋聚合物在手性识别、不对称催化等方面显示出许多独特的性能。在高效液相色谱的手性固定相中，聚甲基丙烯酸三苯甲基酯及其衍生物被广泛应用，但存在易醇解而丧失手性识别能力的问题。我们考虑利用带多吡啶基的螺旋聚醚来从根本上解决其结构上的固有缺陷。另外，由于铀及其化合物有着特殊分子识别与催化性能，使用带多吡啶基的单手性的螺旋聚醚与铀酰离子配位，制备含铀催化剂，依靠聚醚的螺旋结构诱导来研究不对称催化作用。.主要研究内容：.1、合成含吡啶基的手性环氧化合物。.2、通过阴离子聚合反应，将手性环氧单体合成单手性螺旋聚醚。.3、选取适当的螺旋聚醚，制备手性固定相，研究手性识别能力。.4、通过铀与含多吡啶基的螺旋聚醚配位，制备铀-聚醚新型催化剂，研究不对称催化作用。.重要结果和关键数据：.1、合成了多吡啶基的手性环氧化合物10种（e.e.值>97.6%）。.分别是(R)和(S)-3-(4,5-二氮杂芴-9-基)-1,2-环氧丙烷(a)、(R)和(S)-3-(9-乙基-4,5-二氮杂芴-9-基)-1,2-环氧丙烷(b)、(R)和(S)-3-[9-乙基-(4,5-二氮杂芴)-9-基]氧基-1,2-环氧丙烷(c)、(R)和(S)-3-[9-苯基-(4,5-二氮杂芴)-9-基]氧基-1,2-环氧丙烷(d)，(R)和(S)-[((1’-乙基-1’,1’-(2-二吡啶基))甲基]氧基-2,3-环氧丙烷(e)。.2、通过阴离子本体聚合和溶液聚合，制备单手性螺旋聚醚8种，分是聚-(R)-a、聚-(S)-a、聚-(R)-b、聚-(S)-b、聚-(R)-c、聚-(S)-c、聚-(R)-d、聚-(S)-d。.3、选取聚-(R)-b、聚-(S)-b、聚-(R)-c、聚-(S)-c制备成多吡啶基螺旋聚醚的手性固定相，研究手性识别能力。虽然解决了醇解问题，但发现没有预想中的良好手性识别效果，可能是硅胶上键合的量不足，柱效不够高。.4、通过铀与含多吡啶基的螺旋聚醚配位，制备了铀-聚醚新型催化剂，目前正在研究催化性能。.科学意义：. 通过研究，掌握了含多吡啶基手性环氧化合物及单手性螺旋聚醚的合成方法；成功将该螺旋聚醚制备成手性固定相，并应用于高效液相色谱，解决了聚酯类化合物易醇解的问题，但手性识别能力没有达到预期效果。成功制备了铀-聚醚催化剂，为继续研究不对称催化奠定基础。