可见光催化的苯磺酰甲基化及脱苯磺酰基反应研究

发布时间：2018-09-03 11:23

【摘要】：甲基化反应是构建C-C键的重要手段之一,对于有机合成包括制药工业非常重要,因此甲基化反应一直都是化学家们研究的重点。光催化反应因为反应条件温和、简单高效、绿色环保等优点逐渐成为有机合成研究领域的热点。因此研究可见光催化的甲基化反应很有意义。本文主要分为三个部分:第一章:综述了常见的甲基化反应类型,包括常见的非自由基历程甲基化反应和自由基历程的甲基化反应,过渡金属催化的甲基化反应和光催化的甲基化反应。第二章:可见光催化的苯磺酰甲基化反应研究。该反应条件温和,以廉价易得的溴代苯甲砜作为原料。反应过程中通过可见光催化循环,溴代苯甲砜发生单电子转移,生成苯磺酰甲基自由基,该自由基不仅会与芳香杂环发生分子间自由基加成反应,实现杂环的苯磺酰甲基化,还能与N-芳基丙烯酰胺衍生物发生自由基串联反应,生成苯磺酰甲基化的吲哚酮类化合物。第三章,可见光催化的脱苯磺酰基反应研究。该章阐述了两种不同的可见光催化脱苯磺酰基的方案,一种方案是在体系内引入叔丁醇钾参与反应,生成杂环亚甲基自由基,然后在氢供体参与下,达到脱苯磺酰基的目的;另一种方案是底物中富电荷的苯环参与光催化循环,发生单电子转移,从而引发苯环与磺酰基的C-S键均裂,释放一分子二氧化硫,实现脱苯磺酰基的目的。但是这两种方案都没能取得预想的结果。
[Abstract]:Methylation reaction is one of the most important methods to construct C-C bond, which is very important for organic synthesis, including pharmaceutical industry, so methylation reaction is always the focus of chemists. Photocatalytic reaction has become a hotspot in the field of organic synthesis because of its mild reaction conditions, simple and efficient, green environmental protection and so on. Therefore, the study of visible light-catalyzed methylation is of great significance. This paper is mainly divided into three parts: chapter 1: review the common types of methylation reactions, including the common non-radical process methylation reaction and free radical process methylation reaction. Transition metal catalyzed methylation and photocatalytic methylation. Chapter 2: visible light catalyzed benzene sulfonyl methylation. The reaction conditions were mild and the easily available brominated benzyl sulfoxide was used as the raw material. In the process of reaction, a single electron transfer of brominated benzyl sulfoxide occurs in the process of reaction by visible light catalysis. The radical can not only react with aromatic heterocycles to produce intermolecular radical addition, but also realize the benzyl sulfonyl methylation of heterocyclic compounds. It can also react with N-aryl acrylamide derivatives in series to form benzenesulfonyl methylated indole ketones. In chapter 3, visible light catalyzed debenzenesulfonyl reaction was studied. In this chapter, two different schemes of visible light catalyzed desulfonylation of benzenesulfonyl groups are described. One scheme is to introduce potassium tert-butanol into the system to form heterocyclic methylene free radicals, and then debenzenesulfonyl groups can be achieved with the participation of hydrogen donors. Another scheme is that the charge-rich benzene ring in the substrate participates in the photocatalytic cycle, resulting in a single electron transfer, which leads to the splitting of the C-S bond between the benzene ring and the sulfonyl group, and the release of a molecule of sulfur dioxide to achieve the purpose of removing benzenesulfonyl group. But neither of these schemes has produced the desired results.
【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O621.25

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