聚苯乙烯纳米微球负载多功能有机催化剂的制备及其在不对称串联反应中的应用

发布时间：2018-06-03 05:32

本文选题：J?rgensen-Hayashi有机催化剂 + 多功能聚苯乙烯纳米微球　；参考：《西南大学》2017年硕士论文

【摘要】：近年来,不对称有机催化在合成医药中间体、天然产物和生物活性分子等方面显现出卓越的催化性能。二芳基脯氨醇硅醚催化剂(J?rgensen-Hayashi催化剂)由于其在Michael/Aldol、Michael/Henry、Michael/Michael等不对称反应中的高反应活性和高立体选择性而成为不对称有机催化的明星催化剂。然而,由于J?rgensenHayashi催化剂在催化反应中存在加入量大(10-30 mol%)、大都需要等摩尔量外加酸作为助催化剂,反应结束后催化剂难以分离、回收并重复使用等弊端。基于绿色化学的理念,J?rgensen-Hayashi催化剂及其助催化剂的负载回收策略受到越来越多的关注。本文以Boc-L-脯氨酸为原料,经甲基化和亲核加成等反应合成α,α-二苯乙烯基脯氨醇Pro和α,α-二苯乙烯基脯氨醇三甲基硅醚ProTMS(J?rgensen Hayashi催化剂)。采用乳液聚合法将Pro与丙烯酸(AA)和苯乙烯(St)等单体聚合,制备得到纳米聚合物微球Poly(St-co-Pro-co-AA)E,继而用三氟甲磺酸三甲基硅酯(TMSOTf)对聚合物中脯氨醇Pro的羟基进行硅醚化,制备聚苯乙烯纳米微球负载多功能有机催化剂Poly(St-co-ProTMS-co-AA)E,并通过改变不同物质加入量等制备条件调控其形貌和催化性能。用N2吸附-脱附、SEM、IR和元素分析等手段对其结构、形貌和有机催化剂负载量等进行表征。将非均相多功能有机催化剂Poly(St-co-ProTMS-co-AA)E用于肉桂醛和苯并呋喃酮的Michael/Michael/aldol不对称串联反应,以催化性能为参数筛选出最佳的负载多功能催化剂2e4。并用2e4探索了反应的溶剂种类、温度和负载催化剂用量对催化反应的影响,在最佳催化条件下2e4催化不同取代基的α,β-不饱和醛和苯并呋喃酮的不对称Michael/Michael/aldol串联反应表现出与均相催化反应相当的催化活性和对映选择性,反应产物的收率38-75%,ee值95-99%,dr值19:1。催化反应结束后,通过简单的离心即可回收负载催化剂,使用5次后,催化活性略有降低。将负载催化剂2e4催化α,β-不饱和醛和3-甲基环己烯基亚丙基腈的[4+2]环加成反应,在最佳催化条件下探究了不同α,β-不饱和醛与3-甲基环己烯基亚丙基腈反应的催化性能,取得了较好的效果:76-86%收率,ee值87-99%,dr值19:1。
[Abstract]:In recent years asymmetric organic catalysis has shown excellent catalytic performance in the synthesis of pharmaceutical intermediates natural products and bioactive molecules. The diarylproline silyl ether catalyst has become the star catalyst for asymmetric organic catalysis because of its high activity and high stereoselectivity in the asymmetric reactions of Michael / Aldoline Michael / Henry and Michael / Michael etc. However, due to the large amount of 10-30 mol / L J?rgensenHayashi catalyst in the catalytic reaction, the same molar amount of acid is needed as the co-catalyst, the catalyst is difficult to be separated, recovered and reused after the reaction. Based on the concept of green chemistry, more and more attention has been paid to the loading recovery strategy of JGensen-Hayashi catalyst and its cocatalyst. In this paper, 伪 -diphenylvinyl proline (Pro) and 伪, 伪 -diphenylvinyl proline (ProTMS(J?rgensen) were synthesized from Boc-L-proline by methylation and nucleophilic addition reaction. Polymer microspheres Poly (St-co-Pro-co-AAE) were prepared by emulsion polymerization of Pro with monomers such as acrylic acid (AA) and styrene-butadiene (St). The hydroxyl groups of proline Pro in the polymer were then etherified by trimethylsilyl trifluorosulfonate (TFM). Polystyrene nanospheres were prepared and their morphology and catalytic properties were controlled by changing the preparation conditions of polystyrene nanospheres supported polystyrene St-co-ProTMS-co-AAE. The structure, morphology and loading amount of organic catalyst were characterized by N2 adsorption-desorption IR and elemental analysis. The heterogeneous multifunctional organic catalyst Poly(St-co-ProTMS-co-AA)E was used in the asymmetric Michael/Michael/aldol series reaction of cinnamaldehyde and benzofuranone. The best supported multifunctional catalyst 2e4 was selected by using the catalytic performance as the parameter. The effects of solvent type, temperature and the amount of supported catalyst on the catalytic reaction were investigated by 2e4. The asymmetric Michael/Michael/aldol series reaction of 伪, 尾 -unsaturated aldehyde and benzofuranone with different substituents was catalyzed by 2e4 under the optimum conditions. The catalytic activity and enantioselectivity of the asymmetric Michael/Michael/aldol reaction were comparable to those of homogeneous catalytic reaction. The yield of the product was 38-75 and 95-99dr value of 19: 1. After the catalytic reaction was finished, the supported catalyst could be recovered by simple centrifugation, and the catalytic activity decreased slightly after 5 times of use. The [42] cycloaddition reaction of 伪, 尾 -unsaturated aldehydes with 3-methylcyclohexenecylonitrile was catalyzed by supported catalyst 2e4. The catalytic properties of the reactions of 伪, 尾 -unsaturated aldehydes with 3-methylcyclohexenylphenylallylonitrile were investigated under the optimum conditions. A good result was obtained: the yield of 76-86% was 87-99% and the value of dr was 19: 1.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O621.251

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