开发新型N,N-双齿配体及其钯配合物在交叉偶联反应中的应用
发布时间：2019-03-27 12:19
【摘要】：过渡金属催化的成键反应是有机合成化学的前沿,其中偶联反应是构建碳碳、碳杂原子键最有效的方法之一。Suzuki反应和Heck反应是多种偶联反应中应用最广泛的两类反应。催化剂在反应中起着至关重要的作用,而配体通过调节改善中心金属的电子、空间环境从而起到活化金属的催化活性、延长催化剂寿命等作用,因此,开发新型配体一直是开发高效催化剂的研究重点。常用的配体通常是含有孤对电子的O、N、P、S等的有机化合物。N配体金属催化剂在催化反应中显示了良好的催化活性,但在Pd催化的偶联反应中催化活性比P配体催化剂存在显著差异。通常认为P配体更容易在电子效应和空间效应方面进行修饰,而且P和金属之间还存在p反馈作用。但是,氮配体通常对水、氧不敏感,相对容易合成,这些特点对化学家们仍充满吸引力。本论文在简述双齿氮配合物及其在偶联反应等应用的研究进展基础上,重点展开以下三个方面的研究成果1.从电子效应和位阻效应角度考虑,以5,6,7-三氢喹啉-8-酮、胺、PdCl_2为原料,设计并合成了5,6,7-三氢-8-亚胺喹啉系列Pd配合物。方法有分步合成和一锅法两种,通过对Pd催化剂的结构表征,尤其是单晶X-衍射,得知亚胺上的芳基的位阻效应和电子效应对催化剂的结构影响很大。2.将新合成的催化剂Pd1-Pd6,应用于Suzuki偶联反应。以对甲基溴苯和苯硼酸为标准底物优化反应条件。结果表明,在甲苯中以碳酸钾作碱,使用0.001 mol%量的Pd6催化剂能使反应完全转化。同时发现配体位阻大、供电能力强的Pd5和Pd6,催化活性明显高于Pd1-Pd4,最高TON值可达到4.7×10~6。并在优化条件下,开展了底物拓展研究。实验结果表明,各类芳基溴底物均能获得很好的收率。3.论文将催化剂Pd6应用于Heck偶联反应。通过对溶剂、温度、苯乙烯用量以及催化剂用量等条件进行优化。发现以DMF作溶剂,0.001 mol%量的Pd6,130℃,1.2 eq.苯乙烯条件下,对位带给电子基团芳基溴代物可以很好地转化为反式产物;适当增加催化剂用量或提升温度,对位带吸电子基团的芳基溴代物、杂环溴代物也可以很好地完成C-C偶联反应。
[Abstract]:Transition metal-catalyzed bonding reaction is the frontier of organic synthesis chemistry, among which coupling reaction is the most effective method to construct carbon and carbon hetero-atomic bonds. Suzuki reaction and Heck reaction are the two most widely used reactions in many coupling reactions. Catalysts play an important role in the reaction, and ligands improve the electron of the central metal by regulating the space environment, thus play an active role in the catalytic activity of the metal, prolong the life of the catalyst and so on, so that the ligand can improve the electron of the center metal and the space environment. The development of new ligands has always been the focus of research on the development of high-efficiency catalysts. Most commonly used ligands are organic compounds such as O, N, P, S, which contain solitary pairs of electrons. N ligand metal catalysts show good catalytic activity in catalytic reactions. However, the catalytic activity of Pd-catalyzed coupling reaction was significantly different than that of P-ligand catalyst. It is generally believed that P ligand is more easily modified in electron and space effects, and there is p feedback effect between P and metal. However, nitrogen ligands are usually insensitive to water and oxygen and are relatively easy to synthesize, which are still attractive to chemists. In this paper, on the basis of summarizing the research progress of binodentate nitrogen complexes and their applications in coupling reactions, the following three aspects of research achievements are focused on. Taking 5,6,7-trihydroquinoline-8-one, amine and PdCl_2 as raw materials, 5,6,7-trihydro-8-imino-quinoline series Pd complexes were designed and synthesized from the point of view of electron effect and steric hindrance effect. The structure of Pd catalyst was characterized by single crystal X-ray diffraction. It was found that the steric and electronic effects of aryl groups on imines had great influence on the structure of the catalyst. 2. The newly synthesized catalyst Pd1-Pd6, was applied to Suzuki coupling reaction. The reaction conditions were optimized by using p-methyl bromobenzene and phenylboric acid as standard substrates. The results showed that the reaction could be completely transformed by using 0.001 mol% Pd6 catalyst with potassium carbonate as base in toluene. At the same time, it was found that the catalytic activities of Pd5 and Pd6, with high ligand hindrance and strong power supply ability were significantly higher than that of Pd1-Pd4, with the highest TON value of 4.7 脳 10 脳 6. Under the optimized conditions, the substrate expansion research was carried out. The experimental results show that all kinds of aryl bromine substrates can obtain good yields. 3. In this paper, the catalyst Pd6 was applied to Heck coupling reaction. The solvent, temperature, styrene dosage and catalyst dosage were optimized. It was found that using DMF as solvent, the Pd6130 鈩，
本文编号：2448170
[Abstract]:Transition metal-catalyzed bonding reaction is the frontier of organic synthesis chemistry, among which coupling reaction is the most effective method to construct carbon and carbon hetero-atomic bonds. Suzuki reaction and Heck reaction are the two most widely used reactions in many coupling reactions. Catalysts play an important role in the reaction, and ligands improve the electron of the central metal by regulating the space environment, thus play an active role in the catalytic activity of the metal, prolong the life of the catalyst and so on, so that the ligand can improve the electron of the center metal and the space environment. The development of new ligands has always been the focus of research on the development of high-efficiency catalysts. Most commonly used ligands are organic compounds such as O, N, P, S, which contain solitary pairs of electrons. N ligand metal catalysts show good catalytic activity in catalytic reactions. However, the catalytic activity of Pd-catalyzed coupling reaction was significantly different than that of P-ligand catalyst. It is generally believed that P ligand is more easily modified in electron and space effects, and there is p feedback effect between P and metal. However, nitrogen ligands are usually insensitive to water and oxygen and are relatively easy to synthesize, which are still attractive to chemists. In this paper, on the basis of summarizing the research progress of binodentate nitrogen complexes and their applications in coupling reactions, the following three aspects of research achievements are focused on. Taking 5,6,7-trihydroquinoline-8-one, amine and PdCl_2 as raw materials, 5,6,7-trihydro-8-imino-quinoline series Pd complexes were designed and synthesized from the point of view of electron effect and steric hindrance effect. The structure of Pd catalyst was characterized by single crystal X-ray diffraction. It was found that the steric and electronic effects of aryl groups on imines had great influence on the structure of the catalyst. 2. The newly synthesized catalyst Pd1-Pd6, was applied to Suzuki coupling reaction. The reaction conditions were optimized by using p-methyl bromobenzene and phenylboric acid as standard substrates. The results showed that the reaction could be completely transformed by using 0.001 mol% Pd6 catalyst with potassium carbonate as base in toluene. At the same time, it was found that the catalytic activities of Pd5 and Pd6, with high ligand hindrance and strong power supply ability were significantly higher than that of Pd1-Pd4, with the highest TON value of 4.7 脳 10 脳 6. Under the optimized conditions, the substrate expansion research was carried out. The experimental results show that all kinds of aryl bromine substrates can obtain good yields. 3. In this paper, the catalyst Pd6 was applied to Heck coupling reaction. The solvent, temperature, styrene dosage and catalyst dosage were optimized. It was found that using DMF as solvent, the Pd6130 鈩，
本文编号：2448170
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