作者:       李延年
论文题目:   芳基酰胺膦配体用于室温下氯代芳烃和溴代芳烃/烯烃的Suzuki-Miyaura偶联反应
学位:      博士
年份:      2008
摘要:      Suzuki-Miyaura 偶联反应是一种从卤代芳烃和烯烃与各种硼试剂反应来形成C-C 键的有效方法,在有机合成中发挥着重要的作用。该反应具有反应条件温和、可适用于多种活性官能团、受空间位阻影响不大、产率高以及芳基硼酸等试剂经济易得且对潮气不敏感等优点,因而在精细医药中间体合成中得到广泛应用            

                        钯催化剂是Suzuki 偶联反应的重要因素,选择合适的催化剂不仅能够使反应条件变得比较温和而且能够提高反应产率,甚至能使原本不能发生的反应变为可能。由金属钯和膦配体组成的催化剂体系是Suzuki 偶联反应中一类除含氮卡宾钯络合物以外的重要催化剂,而富电子、大位阻膦配体更是高效催化剂的核心部分

                        本博士学位论文主要总结了对芳基酰胺衍生的膦配体的研究,以及该类型配体与Pd(OAc)2 组成的催化剂在室温下催化氯代芳烃、溴代芳烃、溴代烯烃分别同芳基硼酸、烯基硼酸及烷基硼试剂进行的Suzuki 偶联反应中的表现。论文主要分为四个部分:

                        第一章简述了Suzuki 偶联反应及近年的进展,介绍了近年来在研究高效催化剂方面的一些进展,并包括不同的底物,催化剂以及在合成中的应用等等。

            第二章主要研究了芳基酰胺衍生的膦配体在不活泼的氯代芳烃同芳基硼酸在室温下的Suzuki 偶联反应中的应用。通过我们首次提出的“自助分子剪裁”的概念从单一起始物快速合成和筛选了一系列膦配体,并发现C4 位含3-硝基苯基的的膦配体和醋酸钯联用可以在室温下顺利地催化不活泼氯代芳烃和芳基硼酸的偶联反应,反应条件温和且产物收率很高。

            第三章总结了芳基酰胺衍生的膦配体用于室温下烯基硼酸同溴代芳烃的Suzuki 偶联反应。多种溴代芳烃包括十分不活泼和大位阻底物都可以顺利地与烯基硼酸发生偶联,并且收率很高,对于活泼的氯代芳烃,同样有着不错的结果。

            第四章主要介绍了芳基酰胺衍生的膦配体在室温下烷基硼试剂的Suzuki 偶联反应中的表现。该类型配体对烷基硼试剂与溴代芳烃和烯烃的Suzuki 偶联反应有着很好的效果,并且被成功地用于一系列氯代芳烃的反应,但反应温度为50 ºC

                        论文的最后部分列出了主要的实验步骤和化合物的谱图数据以及参考文献等

关键词:    芳基酰胺衍生的膦配体、室温、Suzuki-Miyaura 偶联反应

Author:             Yannian LI
Title:                 Aromatic Amide-Derived Phosphines for Room Temperature Suzuki-Miyaura Cross-Coupling reactions of Aryl Chlorides and Aryl/Vinyl Bromides
Degree:            PhD
Year:                2008
Abstract:          Suzuki-Miyaura, previously known as Suzuki, cross-coupling is an efficient tool for carbon-carbon bond formation under mild conditions and it plays an important role in organic synthesis. The reaction features a number of advantages such as tolerance to a variety of functional groups, being less sensitive to steric bulkiness, high yielding, availability of aryl boronic acids and related equivalent boron reagents, and stability of the boron reagents toward moisture. The protocol has been widely adopted in synthesis of fine pharmaceutical intermediates.

                        Palladium catalyst is a critical factor for successful Suzuki cross-coupling. Selection of an appropriate catalyst is not only to promote the reaction under milder conditions but also to improve the product yield. In some cases, an active catalyst can make a reaction occurring otherwise it might be impossible to take place. Palladium and phosphine ligands constitute an important catalyst type for Suzuki cross-coupling in addition to the palladium-N-heterocyclic carbene complexes. An electron-rich and sterically bulky phosphine is the core component of a high-performing catalyst.

                        This PhD thesis mainly summarizes the original results on studies of aromatic amide-derived phosphines (Aphos), including the precatalyst system consisting of Aphos and Pd(OAc)2 and the applications for promoting room temperature Suzuki cross-coupling of aryl chlorides and aryl/vinyl bromides, respectively, with aryl/vinyl boronic acids, and alkyl boranes.

                        Chapter 1 briefly introduces the recent progress in Suzuki cross-coupling reaction, covering advances made in development of high-performing catalysts and in applications of different types of substrates and catalysts in organic synthesis.

                        Chapter 2 presents our studies on aromatic amide-derived phosphine (Aphos) applied to room temperature Suzuki cross-coupling of unactivated aryl chlorides with aryl boronic acids. By following the “self-assisted molecular editing” (SAME) protocol first established in our labs, a number of Aphos ligands were efficiently prepared from a single starting material and they were screened for catalytic efficacy, leading to the discovery of the best-performing Aphos appended with a 3-nitrophenyl group at the C4 position. Combination of this Aphos with Pd(OAc)2 offers a precatalyst for successful cross-coupling of unactivated aryl chlorides with aryl boronic acids at room temperature. The reactions took place under mild basic conditions to produce the products in high yields.

                        The following Chapter 3 summarizes the results of room temperature Suzuki cross-coupling of vinyl boronic acids with aryl and vinyl bromides by using the Aphos possessing a 2,6-dimethylphenyl group at the C4 position as the ligand to Pd(OAc)2. Various aryl bromides including very inactive and sterically hindered substrates underwent smooth reactions with vinyl boronic acids to furnish the products in excellent yields. For activated aryl chlorides, similar outcome was obtained for the room temperature cross-coupling with vinyl boronic acids.

                        Finally, the room temperature Suzuki cross-coupling reactions were extended to aryl and vinyl bromides with alkyl boranes under the same reaction conditions optimized for the reactions of vinyl boronic acids. The Aphos-Pd(OAc)2 system was proved very efficient for the coupling of alkyl boranes and the results are collected in Chapter 4. At the temperature of 50 ºC, a variety of aryl chlorides successfully coupled with alkyl boranes as well.

                        The experimental section, compound characterization data, and references are found at the end of the thesis, together with copies of both 1H and 13C NMR spectra of the new compounds synthesized during this thesis research.

Keywords:       aromatic amide-derived phosphines, room temperature, Suzuki-Miyaura cross-coupling