过渡金属催化卤代芳烃胺化反应的研究进展

过渡金属催化卤代芳烃的胺化是合成芳胺化合物的重要方法,本文综述了近年来过渡金属催化卤代芳烃与胺等不同含氮化合物的胺化反应研究进展。钯和铜是近几年卤代芳烃胺化反应的热点,重点讨论了钯催化下卤代芳烃与各类胺反应以及铜催化下卤代芳烃胺化反应的研究进展。     

钯催化卤代芳烃氨解反应的研究进展

钯催化卤代芳烃进行氨解反应是构建C-N键的重要方法,由于该方法所需的催化剂量少、反应条件温和、应用范围广和操作简单,因而被广泛应用于芳香胺类化合物的制备与生产。本文对该反应机理进行了简介,对近年来钯催化卤代芳烃与氨、伯胺、仲胺和其他含氮化合物的氨解反应研究进展进行了综述。指出迄今为止高活性和高选择性的催化剂依然有限,氨作为氨解剂和低廉的氯代芳烃作为氨解底物的使用都还不够广泛。寻找新的配体、设计新的催化体系、提高反应选择性和改善反应对敏感官能团的容忍性,是钯催化卤代芳烃氨解反应领域未来的发展方向。另外,仔细研究反应机理将会加深对反应的理解。     

Suzuki偶联反应中钯配合物催化剂的研究进展

Suzuki偶联反应是在零价钯配合物催化剂的催化下,芳基硼酸与卤代芳烃进行的交叉偶联反应,可以高效、高选择性地构建C-C键.钯配合物催化剂对Suzuki偶联反应的活性和选择性起着决定性的影响,是研究Suzuki偶联反应的关键.对含有膦配体、N-卡宾配体、亚胺配体、胺配体和其它配体的钯配合物催化剂催化效果进行了综述.     

单硝基苯胺类化合物的相转移催化合成

芳胺是染料合成中重要的中间体。卤代芳烃的氨(胺)化反应是在芳环上引进氨基的一条重要途径。使这类芳香族的亲核取代反应一般难以进行。加上胺类沸点较低,单硝基氯苯的胺化都要在高温高压下才能进行。为了缓和反应条件,人们进行了一些研究。传统的方法是采用铜盐催化,条件仍较苛刻。Rondestveat报导在甲酰胺中,邻硝基氯苯与氨在200℃反应,可以得到较好的收率。林富钦等研究了以硫酸铜和醋酸钠为催化剂,以甲酰胺为溶     

由卤代芳硝基物制备卤代芳胺的综述

综述了由卤代芳硝基物还原制备卤代芳胺的三类方法,对三类还原方法的优缺点进行了对比和讨论,重点介绍了第三类制备卤代芳胺的还原方法-催化加氢还原法,最后介绍了催化加氢还原卤代芳香硝基物的新方法及新领域。     

四齿膦配体在Heck反应中的应用研究

简单介绍了Heck反应,并总结了近几年来以氯代芳烃为底物的Heck反应的研究进展,提出了一些可能对提高催化氯代芳烃活性有作用的新型的四齿膦配体;以二胺为骨架合成了相应的四齿膦配体,该四膦配体的催化体系对含各种官能团的卤代芳烃都表现出了很高的催化活性,即使是非活化溴代芳烃对溴苯甲醚,在钯用量低至0.01 mol%时同样表现出优良催化性能。     

四膦配体/钯体系催化无铜Sonogashira偶联反应

以环己二胺为骨架的含氮四膦配体N,N,N',N'-四[(二苯基膦)甲基]环己二胺和钯组成的催化体系用于苯乙炔和芳卤的Sonogashira反应,该催化体系对卤代芳烃显示了良好的官能团容忍性。结果显示空间位阻的影响大于电子效应,通常能与金属配位使得金属催化剂失活而难以顺利反应的含N杂环化合物,3-溴喹啉以99%的收率获得相应的产物,活性较低的氯代底物,3-氯吡啶的目标产物产率为90%。     

认识非活化溴代芳烃化合物甲氧基化生产技术演进过程,全面培养学生专业思维能力

本文在介绍活化与非活化卤代芳烃化合物甲氧基化反应差异和过渡金属催化非活化卤代芳烃化合物甲氧基化反应的基础上,阐明了可工业化应用的铜催化非活化溴代芳烃化合物甲氧基化工艺的发展进程;通过介绍四代生产技术的实际应用,揭示了甲氧基化工艺研发的渐进过程,有助于学生完整理解工艺发展脉络。应用反应机理理解工艺原理能促使学生形成科学思维方式。     

介孔碳负载纳米Pt高效催化卤代芳香硝基化合物选择性还原制卤代芳胺

卤代芳胺主要通过卤代芳硝基化合物选择性还原制备,但加氢过程中常伴随着不同程度的脱卤反应而降低反应的选择性。本文采用柠檬酸镁快速热解法制备的介孔碳材料(MC-c)做为载体,制备了MC-c负载的高分散Pt纳米粒子(Pt/MC-c),并将其用于多种卤代芳香硝基化合物选择性还原制卤代芳胺。研究结果表明,Pt/MC-c催化剂在选择性还原反应中表现出了较高的反应活性和100%的卤代芳胺选择性。邻氯硝基苯为模型反应物的循环实验表面,Pt含量为2%的2%Pt/MC-c催化剂在循环12次后,反应活性和选择性没有明显变化,仍然保持在78%和100%。表明制备的Pt/MC-c催化剂在卤代芳香硝基化合物选择性还原反应中具有优异的反应稳定性。优异的催化性能主要归因于Pt颗粒与介孔碳载体之间的协同作用。     

芳乙酸类化合物的合成研究进展I

介绍了芳乙酸类化合物的特性,总结了零碳取代芳烃与两碳原子及以上单元直接或间接合成芳乙酸的方法,具体按照芳烃与2个碳原子单元反应法、芳胺经吲哚酮或吲哚醌合成法、卤代芳烃一步引入2个及以上碳原子的合成法合成芳乙酸进行讨论,叙述了这些方法的特点及适用范围。     

A simple and recyclable copper/DTPA catalyst system for amination of aryl halides with aqueous ammonia in water

Commercially available CuO/DTPA (diethylenetriaminepentaacetic acid) was established to be a low-cost, recyclable, and environmentally benign homogeneous catalyst system for direct amination of aryl halides with ammonia. Primary aryl amines can be readily prepared from both electron-withdrawing and electron-donating aryl halides in good yields in water without the addition of surfactants.     

Examination of the Aromatic Amination Catalyzed by Palladium on Charcoal

The Buchwald–Hartwig amination of aryl halides with secondary amines and functionalized aromatic amines catalyzed by solid‐supported palladium is reported. The choices of ligand, base and solvent are crucial for the successful coupling. The amination of aromatic iodides, bromides and chlorides can be easily achieved with palladium on charcoal in the presence of a biphenylphosphane‐type ligand at 80–110 °C. In addition, the palladium on charcoal catalyst is easily separable after the reaction, and reusable several times with only small activity loss.     

Synthesis of Well‐Defined Diphenylvinyl(cyclopropyl)phosphine‐Palladium Complexes for the Suzuki–Miyaura Reaction and Buchwald–Hartwig Amination

The well‐defined diphenylvinylphosphine‐palladium complex 1 and the diphenylcyclopropylphosphine‐palladium complex 2 were successfully synthesized. The crystal structures of these complexes were obtained by X‐ray crystallographic analysis. Both complexes were air‐ and moisture‐stable, and could be prepared on a gram scale. These palladium complexes catalyzed the Suzuki–Miyaura reaction of aryl bromides [turnover numbers (TON) up to 196,000] and aryl chlorides (TON up to 50,000). Furthermore, complex 2 catalyzed the Buchwald–Hartwig amination of aryl chlorides and aromatic/aliphatic amines with a low catalyst loading. These complexes showed different reactivities for the coupling of 2‐chloropyridine, and the origin of this difference is discussed.     

Homogenous bimetallic catalysis on amination of ArX and ArX2 in aqueous medium-synergistic effect of dicopper complexes

A dicopper complex [Cu₂(bpnp)(OH)(CF₃COO)₃] (1) (bpnp = 2,7-bis(pyridin-2-yl)-l,8-naphthyridine) was found to be an excellent catalyst on amination of aryl halides and aryl dihalides with ammonia in aqueous solutions leading to the corresponding anilines and aryldiamines, respectively. Catalytic activity of 1 toward amination appears to be superior to those of other mono nuclear copper complexes. Furthermore, the bimetallic catalyst 1 gave exclusively diamination product in the reaction of ArX₂ with ammonia, but other copper complexes showed poor selectivity. Kinetic product distribution study suggests that the dicopper metal ions in this catalysis promote the second amination efficiently.     

2,6‐Diisopropoxyphenyl(dicyclohexyl)phosphine: A New Ligand for Palladium‐Catalyzed Amination Reactions of Aryl Chlorides with Potassium Hydroxide as the Base

A new, readily available monophosphine tetrafluoroborate salt [ L2 ⋅ HBF₄ ] was developed for the palladium‐catalyzed amination reaction of aryl chlorides in moderate to high yields with the cheap and easily available potassium hydroxide as the base. The reaction enjoys a wide scope, lower reaction temperatures, shorter reaction times, high yields, and low catalyst loading when compared to some of same amination reactions reported in the literature. Based on a kinetic study, ³¹P NMR measurements, and DFT calculations, a mechanism involving a 1:1 Pd/L species is proposed.     

3，5-二溴-2，6-双（2’-嗯唑啉基）苯基钯（Ⅱ）钳型物的合成及其催化Suzuki反应

以4,6-二溴间苯二甲酸为起始原料,经过酰化、氨解、氯化以及成环反应生成配体4,6-二溴-1,3一双（2’-嗯唑啉基）苯。后者先与醋酸钯作用后经离子交换最终得到对应的钳形化合物氯化[3,5-二溴-2,6-双（2’-嗯唑啉基）]苯基钯（Ⅱ）。考察了该钳形化合物催化取代芳氯与苯硼酸的偶合反应。结果表明：除对氯苯胺外,其余各取代芳氯与苯硼酸的偶合均得到较高偶合收率,且带供电子基团的氯苯与苯硼酸的偶合收率要高于吸电子基团氯苯的偶合收率,这可能与钳形化合物中溴的吸电子性能有关。     

Catalytic System for Inhibition of Amination‐Type Reaction and Palladium‐Catalysed Direct Arylation using Non‐Protected Pyrazole Derivatives

The palladium‐catalysed direct arylation at C‐4 of non‐protected 5‐aminopyrazoles was found to proceed in high yields using a variety of aryl bromides. The choice of potassium acetate as the base was found to be crucial to inhibit the amination reaction and to promote the direct arylation.     

A New,Efficient and Recyclable Lanthanum(III) Oxide‐ Catalyzed C?N Cross‐Coupling

A new and efficient protocol for the C N cross‐coupling of aryl halides with heteroaromatic amines in the presence of lanthanum(III) oxide (10 mol%) as a recyclable catalyst, N,N′‐dimethylethylenediamine (DMEDA) (20 mol%) and potassium hydroxide (KOH) as a base in dimethyl sulfoxide (DMSO) at 110 °C has been developed. This inexpensive catalytic system is highly effective towards the amination of aryl halides with various nitrogen nucleophiles and is significantly tolerant towards other functional groups in the substrates.     

Organocatalytic Asymmetric α‐Amination of Unprotected 3‐Aryl and 3‐Aliphatic Substituted Oxindoles using Di‐tert‐butyl Azodicarboxylate

The bifunctional quinine‐derived thiourea catalyst 14 was found to catalyze the direct amination of unprotected 3‐aryl and aliphatic substituted oxindoles with di‐tert‐butyl azodicarboxylate (DBAD) to construct a tetrasubstituted stereogenic carbon center at the C‐3 position of oxindoles in good to excellent yield and enantioselectivity.     

Heterogenized copper catalysts for the amination of arylhalide: Synthesis,characterization and catalytic applications

This research investigated the synthesis, characterization and catalytic activity of heterogenized copper complexes for the selective amination of aryl halides. Amination reactions using homogeneous copper catalyst systems are not generally selective and it is also difficult to recover the catalyst from the homogeneous system for recycling. To overcome these difficulties, our efforts were directed towards the development of cheaper heterogeneous catalyst systems, which can be easily recovered and recycled. Heterogenized analogs of the homogenous Cu complexes were prepared using two methods: (a) encapsulation of copper complexes in zeolite-Y and (b) tethering of copper complexes on various supports like zeolite-Y, silica, charcoal, or clay. The encapsulated and tethered copper catalysts on zeolite-Y were characterized using EPR, Diffused reflectance UV–vis, XRD, IAS, ICPES, SEM, and TEM. The results confirmed that the copper complexes were truly heterogenized in zeolite-Y support. Encapsulated and tethered copper complexes were tested for amination of aryl iodide. The effects of various reaction parameters were examined using tethered Cu(Phen)(PPh₃)Br-PTA-Y catalyst to determine optimum conditions. A recycle study of encapsulated and tethered Cu catalyst was carried out to test their robustness for possible commercial exploitation.