非膦钯配合物的合成及其催化直接芳基化反应与Suzuki反应的研究
发布时间：2018-11-17 16:01
【摘要】：通过C-C偶联反应可以合成含有芳环-芳环、芳环-杂环或杂环-杂环结构的化合物,在天然产物、医药、农药、电子材料等方面有着非常广泛的应用。而C-H键直接芳基化和Suzuki偶联反应是C-C偶联中非常高效的方法,不仅条件温和、绿色环保和成本低廉,而且原料性质稳定、易于贮存。用于催化上述反应的配体大都为膦配体,膦配体在位阻效应和电子效应方面都很优秀,表现出了很好的催化活性,然而,膦配体在空气下很不稳定、毒性较大,限制了其大规模应用。因此,开发出催化活性优良、对空气稳定的非膦配体,已成为有机催化领域的热点。1.设计并合成了3个大位阻二亚胺钯配合物,对其结构进行了1H NMR、13C NMR表征,并对C1和C3两个单晶结构进行了X-射线单晶衍射。通过考察位阻效应对配合物催化活性的影响,我们发现,较大位阻有利于直接芳基化反应。原因在于,还原消除步为决速步的直接芳基化中,位阻最大的二亚胺钯配合物C3可以加快还原消除速度,促进整个催化循环。2.设计并合成了7个大位阻氮杂环卡宾钯配合物,对其结构进行了1H NMR、13C NMR表征,并对K1、K3、K4、K6四个单晶结构进行了X-射线单晶衍射,考察了位阻效应和电子效应对配合物催化活性的影响。通过在骨架上引进苊基和在N-芳环上引进二苯甲基,同时加快了氧化加成与还原消除速度,促进整个催化循环。大π-π共轭苊基骨架能增强π电子给电子能力,提高氧化加成速度;邻位引进大位阻二苯甲基可以提高还原消除速度,对位引进二苯甲基可与氯代芳烃有π-π堆积作用,促进氧化加成步骤。我们发现,在氧化加成为决速步的Suzuki反应中,氮杂环卡宾钯配合物K5的活性最好,而位阻最大的K7活性却很差。其原因在于N-芳环邻位位阻过大,导致配合物失去了柔性,可协调性太差,抑制了氧化加成的进行,因此,位阻适中的K5为最佳催化剂。3.分别将其催化五元杂环及其衍生物C-H键直接芳基化反应、芳基/杂环氯代物与芳基/杂环硼酸的Suzuki反应。考察了配合物的位阻效应、电子效应、碱和溶剂等因素对偶联产率和官能团容忍性的影响。3.1α-二亚胺钯配合物催化C-H键直接芳基化反应的研究结果表明:C1-C3都能有效地在五元杂环α位进行C-H键直接芳基化反应。其中C3的活性最高,最佳反应条件:C3(0.5-0.1 mol%)、K2CO3(2.0 eq)、DMAc作为溶剂,在130 oC下反应12h,GC偶联产率最高可达99%。3.2氮杂环卡宾钯配合物催化Suzuki偶联反应的研究在弱碱、空气条件下,通过K5催化Suzuki偶联反应合成了一系列芳环-芳环、芳环-杂环和杂环-杂环偶联产物,其中K5的催化活性最高,催化剂用量可降低至0.025 mol%。最佳反应条件为:K5作催化剂、K2CO3为碱、无水乙醇作溶剂,在空气下80oC反应4h,GC偶联产率高达99%。
[Abstract]:Compounds containing aromatic ring, aromatic ring or heterocyclic structure can be synthesized by C-C coupling reaction. They have been widely used in natural products, medicine, pesticides, electronic materials and so on. The direct arylation of C-H bond with Suzuki coupling reaction is a very efficient method in C-C coupling. It is not only mild, green and low cost, but also stable in properties of raw materials and easy to store. Most of the ligands used to catalyze the above reactions are phosphine ligands. The phosphine ligands are excellent in the field of steric and electronic effects and exhibit good catalytic activity. However, the phosphine ligands are unstable and toxic in the air. It limits its application on a large scale. Therefore, the development of non-phosphine ligands with excellent catalytic activity and air stability has become a hot spot in the field of organic catalysis. Three large hindrance diimide palladium complexes were designed and synthesized. Their structures were characterized by 1H NMR,13C NMR, and the single crystal structure C1 and C3 were characterized by X-ray single crystal diffraction. By investigating the effect of steric resistance on the catalytic activity of the complexes, we found that the larger steric resistance is beneficial to the direct arylation reaction. The reason is that in the direct arylation of the reduction elimination step, the complex C _ 3, which has the largest steric resistance, can accelerate the reduction removal rate and promote the whole catalytic cycle. Seven carbene palladium complexes with large steric hindrance have been designed and synthesized. Their structures have been characterized by 1H NMR,13C NMR. The effects of steric resistance and electron effect on the catalytic activity of the complexes were investigated. By introducing acenaphthene on the skeleton and diphenyl methyl on the N-aromatic ring, the oxidation addition and reduction elimination rate were accelerated, and the whole catalytic cycle was promoted. The skeleton of large 蟺-蟺 conjugated acenaphthene can enhance the electron feeding capacity of 蟺 and increase the oxidation addition rate. The reduction removal rate can be improved by introducing biphenylmethyl with large steric hindrance at o-site, and 蟺-蟺 stacking with chlorinated aromatics can be obtained by introducing diphenylmethyl to p-position, thus promoting the oxidation addition step. It is found that in the Suzuki reaction, the activity of carbene palladium complex K5 is the best, while the activity of K7 with the largest steric resistance is very poor. The reason is that the N- aryl ring orthosteric resistance is too large, which leads to the loss of flexibility, poor coordination and inhibition of oxidation addition. Therefore, K _ 5 with moderate steric resistance is the best catalyst. It catalyzes the direct arylation of C-H bond and the Suzuki reaction of aryl / heterocyclic chlorides with aryl / heterocyclic boric acid. The steric and electron effects of the complexes were investigated. The effect of alkali and solvent on the coupling yield and the tolerance of functional groups. The results of direct arylation of C-H bond catalyzed by 3.1 伪 -diimide palladium complex show that C1-C3 is effective at the 伪 site of quaternary heterocyclic compounds. Direct arylation of C-H bond was carried out. The best reaction conditions were C3 (0.5-0.1 mol%), K2CO3 (2.0 eq), DMAc as solvent) for 12 h at 130 oC. Studies on the Suzuki Coupling reaction catalyzed by the Palladium complexes of nitrogen heterocyclic Carbenes with a maximum yield of 990.3.2 A series of aromatic rings were synthesized by K _ 5 catalyzed Suzuki coupling reaction under the condition of weak base and air. The coupling products of aromatic ring heterocyclic and heterocyclic are the most active, and the amount of catalyst can be reduced to 0.025 mol%.. The optimum reaction conditions were as follows: K5 as catalyst, K2CO3 as base, anhydrous ethanol as solvent, and 80oC reaction in air for 4 h, the coupling yield of GC was as high as 99wt%.
【学位授予单位】：广东药科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O641.4;O621.251
本文编号：2338380
[Abstract]:Compounds containing aromatic ring, aromatic ring or heterocyclic structure can be synthesized by C-C coupling reaction. They have been widely used in natural products, medicine, pesticides, electronic materials and so on. The direct arylation of C-H bond with Suzuki coupling reaction is a very efficient method in C-C coupling. It is not only mild, green and low cost, but also stable in properties of raw materials and easy to store. Most of the ligands used to catalyze the above reactions are phosphine ligands. The phosphine ligands are excellent in the field of steric and electronic effects and exhibit good catalytic activity. However, the phosphine ligands are unstable and toxic in the air. It limits its application on a large scale. Therefore, the development of non-phosphine ligands with excellent catalytic activity and air stability has become a hot spot in the field of organic catalysis. Three large hindrance diimide palladium complexes were designed and synthesized. Their structures were characterized by 1H NMR,13C NMR, and the single crystal structure C1 and C3 were characterized by X-ray single crystal diffraction. By investigating the effect of steric resistance on the catalytic activity of the complexes, we found that the larger steric resistance is beneficial to the direct arylation reaction. The reason is that in the direct arylation of the reduction elimination step, the complex C _ 3, which has the largest steric resistance, can accelerate the reduction removal rate and promote the whole catalytic cycle. Seven carbene palladium complexes with large steric hindrance have been designed and synthesized. Their structures have been characterized by 1H NMR,13C NMR. The effects of steric resistance and electron effect on the catalytic activity of the complexes were investigated. By introducing acenaphthene on the skeleton and diphenyl methyl on the N-aromatic ring, the oxidation addition and reduction elimination rate were accelerated, and the whole catalytic cycle was promoted. The skeleton of large 蟺-蟺 conjugated acenaphthene can enhance the electron feeding capacity of 蟺 and increase the oxidation addition rate. The reduction removal rate can be improved by introducing biphenylmethyl with large steric hindrance at o-site, and 蟺-蟺 stacking with chlorinated aromatics can be obtained by introducing diphenylmethyl to p-position, thus promoting the oxidation addition step. It is found that in the Suzuki reaction, the activity of carbene palladium complex K5 is the best, while the activity of K7 with the largest steric resistance is very poor. The reason is that the N- aryl ring orthosteric resistance is too large, which leads to the loss of flexibility, poor coordination and inhibition of oxidation addition. Therefore, K _ 5 with moderate steric resistance is the best catalyst. It catalyzes the direct arylation of C-H bond and the Suzuki reaction of aryl / heterocyclic chlorides with aryl / heterocyclic boric acid. The steric and electron effects of the complexes were investigated. The effect of alkali and solvent on the coupling yield and the tolerance of functional groups. The results of direct arylation of C-H bond catalyzed by 3.1 伪 -diimide palladium complex show that C1-C3 is effective at the 伪 site of quaternary heterocyclic compounds. Direct arylation of C-H bond was carried out. The best reaction conditions were C3 (0.5-0.1 mol%), K2CO3 (2.0 eq), DMAc as solvent) for 12 h at 130 oC. Studies on the Suzuki Coupling reaction catalyzed by the Palladium complexes of nitrogen heterocyclic Carbenes with a maximum yield of 990.3.2 A series of aromatic rings were synthesized by K _ 5 catalyzed Suzuki coupling reaction under the condition of weak base and air. The coupling products of aromatic ring heterocyclic and heterocyclic are the most active, and the amount of catalyst can be reduced to 0.025 mol%.. The optimum reaction conditions were as follows: K5 as catalyst, K2CO3 as base, anhydrous ethanol as solvent, and 80oC reaction in air for 4 h, the coupling yield of GC was as high as 99wt%.
【学位授予单位】：广东药科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O641.4;O621.251
【参考文献】
相关硕士学位论文 前1条
1 雷小莉;钯催化的选择性偶联反应合成2-吡喃酮类化合物及铜催化的Chan-Lam偶联反应研究[D];江西师范大学;2011年
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