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聚烯烃是消费量最大、应用最广泛的合成树脂。在聚烯烃结构中引入少量功能性基团,能够在保持聚烯烃固有优异性能的前提下,赋予聚烯烃极性、反应性、粘接性、抗氧化性、荧光性等多种功能特性,从而得到具有重要应用前景的功能化聚烯烃。后功能化法是制备功能化聚烯烃的主要方法之一。传统熔融自由基接枝(FRG)反应可控性低、副反应多,难以制备结构明确的高接枝量产物。使用新型引发体系,可提高FRG反应可控性,抑制副反应、提高接枝量。相比FRG反应,碳氢活化反应可控性强,可引入的功能性基团品类丰富,可用于高效合成结构明确、无副反应的新颖功能化聚烯烃。本文在简述FRG反应制备功能化聚烯烃的基础上,着重讨论近年来基于碳氢活化反应制备功能化聚烯烃的最新研究进展。 相似文献
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过渡金属催化导向碳氢键活化与不饱和分子的环化反应已成为合成复杂碳环和杂环化合物的高效途径,但反应中往往需要额外加入化学计量化学氧化剂来实现反应循环.电化学有机合成可利用电流代替昂贵、有毒的化学氧化剂,是一种环境友好的绿色合成手段.近年来,电化学有机合成与过渡金属(如Pd、Ni、Co、Ru、Cu、Rh、Ir等)催化碳氢键活化的结合取得了显著的进展.重点介绍了过渡金属催化导向C—H活化与炔烃、烯烃、一氧化碳和异氰等不饱和分子的电氧化环化反应的最新进展,并对该领域未来发展方向进行了展望. 相似文献
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本文分别以离子型导体La_2O_3和CaO载体,添加A_2BO_4型快离子导体,发现催化剂的C_2烃收率与添加的快离子导体迁移能力有很好的顺变关系。 相似文献
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在过去的一二十年里,纳米材料科学的发展主要集中在纳米材料的合成,结构的修饰与表征以及相应的物理性质,而纳米材料在有机反应中的催化还未受到应用的重视。最近具有大的表面积和高反应活性的纳米形态受到广泛的关注。利用晶型的纳米金属粒子作为催化剂在有机合成领域得到了越来越多的应用,本综述主要概括了各种金属纳米粒子在偶联反应中的应用,包括C-C键、C-N键、C-O键和C-S键的形成。 相似文献
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采用柠檬酸法制备了Ca,Sr共掺杂的CeO_2催化剂,发现共掺杂催化剂较单掺杂或未掺杂催化剂呈现出更好的催化甲烷氧化偶联(OCM)反应性能.通过表征可知,Ca,Sr共掺杂催化剂的物相为CeO_2和SrCO_3,Ca高度分散或掺杂于CeO_2之中;CeO_2的粒径明显变小;表面呈中等程度碱性;Ce基催化剂上的亲电氧物种数量随着碱土金属的掺杂而增大,亲电氧物种与晶格氧摩尔比(O_2-2+O-2)/O-2的大小顺序(CeSrCaCe SrCeO_2)与C2选择性一致;且SrCO_3相的存在有助于Ce基氧化物催化甲烷氧化偶联反应(OCM)性能的改善. 相似文献
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Many nitrogen- and sulfur-containing heterocyclic compounds exhibit biological activity. Among these heterocycles are benzo[4,5]thiazolo[2,3-c][1,2,4]triazoles for which two main synthetic approaches exist. Here we report a new synthetic protocol that allows the preparation of these tricyclic compounds via the oxidation of a mercaptophenyl moiety to its corresponding disulfide. Subsequent C-H bond functionalization is thought to enable an intramolecular ring closure, thus forming the desired benzo[4,5]thiazolo[2,3-c][1,2,4]triazole. This method combines a high functional group tolerance with short reaction times and good to excellent yields. 相似文献
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过渡金属催化的碳氢官能团化反应具有原子经济性高、区域选择性好和合成路线简短等优点,近年来得到了化学家们的广泛关注,是当前有机合成化学的热门研究领域之一.近几年来,稀土金属催化剂也逐渐被开发应用于该领域,得到优异的结果,同时也表现出一些独特的催化活性.本文综述了稀土金属络合物催化的碳氢官能团化反应,主要包括C-H烷基化反... 相似文献
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Soukaina Faarasse Nabil El Brahmi Grald Guillaumet Saïd El Kazzouli 《Molecules (Basel, Switzerland)》2021,26(19)
The regioselective C-H functionalization of the five-membered ring of the 6,5-fused heterocyclic systems is nowadays well documented due to its high reactivity compared to the six-membered ring. So, developing new procedures of C-H functionalization of the six-membered ring “by thinking out of the box” is extremely challenging, which explains the limited number of reports published to date. This review paper aims to highlight advances achieved in this emerging chemistry research and discusses recently reported methods. 相似文献
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以邻或对位取代苯甲酸为原料,通过羧基导向的芳香羧酸邻位碳氢键官能团化继而发生脱羧反应,在原羧基的邻位引入官能团,可以合成传统付-克反应难以合成的间位取代芳香化合物。在此类反应中,羧基充当无痕导向基的功能。本文综述了基于过渡金属催化羧基无痕导向的芳香羧酸脱羧偶联策略,形成新C―C、C―杂键的研究进展。 相似文献
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The formation of carbon-nitrogen bonds by reaction between a nitrogen atom and an unactivated carbon-hydrogen bond is a highly atom-economical process that attracted the attention of the chemists in the last two decades. The widely useful amination and hydroamination reactions, which furnish acyclic or cyclic products, give access to various nitrogen-containing basic and fine chemicals. This review highlights recent progress in the development of palladium-catalyzed reactions that occur by direct functionalization of simple carbon-hydrogen bonds to give heterocyclic products. Pd(0)- and Pd(II)-catalyzed reactions are described separately, emphasizing the different behavior of the metal in these two oxidation states. 相似文献
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酰胺基团常见于天然产物和药物分子中,利用它们的导向作用完成其普通烷烃C-H键的选择性功能化的相关反应研究在近十年内已取得迅速发展,并且这类反应也将逐渐成为构筑分子骨架、延长碳链和引入官能团的理想方法.本文对过去十年该领域的进展按成键形式、反应物类型分类并以时间顺序排列,依次叙述生成烷烃-芳烃、烷烃-烯烃、烷烃-羰基、烷烃-炔烃及烷烃-烷烃结构的碳-碳键和碳-氮、碳-氧等碳-杂原子键的反应.论述主要集中在反应的表现、改进及其合成应用,以及反应机理讨论等. 相似文献
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Copper-catalyzed trifluoromethylation via oxidative sp3 C-H activation at the α-position of nitrogen in tetrahydroisoquinoline derivatives using DDQ and Ruppert-Prakash reagent has been successfully achieved. The reaction of various amines gave the corresponding trifluoromethylated products in 15-90% yields under mild conditions. 相似文献
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在手性分子中,轴手性化合物占据着非常重要的地位.从原子和步骤经济性方面考虑,利用不对称碳-氢官能团化反应构建轴手性化合物是最简洁高效的方法.随着过渡金属催化的不对称碳-氢键官能团化领域的逐步发展,利用该策略来构建轴手性联芳基化合物的研究成果也不断涌现.本文综述了通过过渡金属钯、铑和铱催化的不对称碳-氢键官能团化反应合成轴手性联芳基化合物的最新进展.此外,还介绍了利用这些方法合成多种轴手性配体及其催化的不对称反应,以及这些方法在天然产物合成中的应用. 相似文献
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Mechanistic Study of Palladium-Catalyzed Oxidative C-H/C-H Coupling of Polyfluoroarenes with Simple Arenes 下载免费PDF全文
Pd-catalyzed oxidative C-H/C-H coupling reaction is an emerging type of C-H acti-vation reaction, which attracts great interests because both reaction partners do not re-quire pre-functionalization. In the present study, we employed DFT methods to investigatethe mechanism of Pd(OAc)2-catalyzed oxidative C-H/C-H coupling of pentafluoroben-zene with benzene. Four possible pathways were examined in the C-H activation part: path A benzene-pentafluorobenzene mechanism (C-H activation of benzene occurs before the C-H activation of pentafluorobenzene), path B pentafluorobenzene-benzene mechanism (C-H activation of benzene occurs after the C-H activation of pentafluorobenzene), path C benzene-pentafluorophenylsilver mechanism (C-H activation of benzene and subsequenttransmetalation with pentafluorophenyl silver complex), path D pentafluorophenylsilver-benzene mechanism (transmetalation with pentafluorophenyl silver complex and subsequent C-H activation of benzene). Based on the calculations, the sequences of two C-H activation steps are found to be different in the oxidative couplings of same substrates (i.e. pentaflu-orobenzene and benzene) in different catalytic systems, where the additive Ag salts played a determinant role. In the absence of Ag salts, the energetically favored pathway is path B (i.e. the C-H activation of pentafluorobenzene takes place before the C-H cleavage of benzene). In contrast, with the aid of Ag salts, the coordination of pentafluorophenylsilver to Pd center could occur easily with a subsequent C-H activation of benzene in the second step, and the second step significantly raises the whole reaction barrier. Alternatively, in thepresence of Ag salts, the kinetically preferred mechanism is path C (i.e. the C-H activation of benzene takes place in the first step followed by transmetalation with pentafluorophenyl-silver complex), which is similar to path A. The calculations are consistent with the H/D exchange experiment and kinetic isotope effects. Thus the present study not only offers a deeper understanding of oxidative C-H/C-H coupling reaction, but also provides helpful insights to further development of more efficient and selective oxidative C-H/C-H coupling reactions. 相似文献