无过渡金属催化条件下咪唑衍生物与炔基溴的炔基化反应研究

以炔基溴和咪唑衍生物为反应原料,详细探讨了无过渡金属催化条件下的咪唑类芳香炔胺化合物的合成方法.研究结果表明,以N,N-二甲基甲酰胺为溶剂、碳酸钾为碱,于80℃下反应12 h即可获得中等偏上收率的碳-氮偶联产物.通过上述方法合成得到了系列芳香炔胺衍生物,其结构经1H NMR和13C NMR表征.     

过渡金属催化端炔的氧化交叉偶联反应研究进展

炔基化合物是有机合成中重要的一类官能团化合物,端基炔通过氧化交叉偶联反应可以制备各种各样新的炔基化合物.总结了近年来端基炔参与的氧化交叉偶联反应,主要介绍了Pd,Cu,Fe等过渡金属催化的端炔氧化交叉偶联反应研究进展.     

无溶剂下胺、炔、炔反应选择性构筑季碳炔丙基胺（英文）

在无溶剂下以胺、炔、炔为原料通过"一锅法"串联的反应方便、高效地合成了季碳炔丙基胺.脂肪炔和芳香炔都可以适用于该反应体系.在脂肪炔反应体系中, AgOTf催化促进胺-炔-炔"马氏"反应进程;当芳香炔作为反应底物时,CuBr_2/Zn(OTf)_2用于共催化剂.该串联反应展示出优异的原子利用效率,为季碳炔丙基胺的制备提供了一种极具有吸引力的绿色合成方法.     

铜纳米颗粒催化的炔、二卤甲烷、胺三组分偶联反应研究

以铜纳米颗粒作为催化剂,Cs2CO3为碱,二卤甲烷为底物和溶剂,发展了一个高效的催化炔、二卤甲烷、胺三组分偶联反应(AHA偶联反应)生成炔丙胺的反应体系.与文献相比,该催化体系具有催化剂廉价易得、反应条件相对温和、底物适应性优良、使用单一溶剂体系后处理方便的特点.同时,以铜纳米颗粒为催化剂,易于实现催化剂的有效循环利用,经5次反应催化活性未见明显下降.     

饱和开链醚的氧化碳氢炔基化研究

首次报道了饱和开链醚和末端炔的交叉脱氢偶联.在Ph₃CCl/GaCl₃介导的温和氧化条件下,饱和开链醚与一系列芳基和烷基末端炔在室温可发生交叉脱氢偶联,反应收率高达73%.鉴于烷基乙炔反应效率较低的问题,还报道了Ph₃CCl/GaCl₃介导的饱和开链醚和一系列烷基取代的炔基硼试剂的氧化偶联,并获得了较好的反应收率.     

膦酰保护基促进选择性Hay偶联制备非对称1,3-二炔（英文）

报道了芳香末端炔烃与单膦酰基-保护二炔的选择性Hay偶联反应. Ph_2P(O)的极性使得产物非对称1,3-二炔易与副产物分离.单膦酰基-保护二炔的低反应活性减少了自身氧化偶联,从而提高了目标产物的产率.很多芳香末端炔烃与单膦酰基-保护二炔都能应用于本Hay偶联反应,且相应非对称1,3-二炔产物的产率为中等到好.产物非对称1,3-二炔能用于合成非对称炔-二炔烃及环多炔烃.     

室温合成羟异丙基保护炔基的一阶苯炔dendrimer

在室温下,使用Sonogashira交叉偶联反应体系,以均三炔苯为核,以较高的收率合成了一种重要的新型芳炔功能单体——羟异丙基保护炔基的一阶间位苯乙炔dendrimer,并用核磁共振氢谱对产物进行了结构鉴定.     

芳炔参与的三组分芳基化反应进展

三组分反应具有操作简单、反应效率高等优势,契合“原子经济、绿色环保”等原则.目前,芳炔参与的无过渡金属催化的芳基化反应主要分为以下三种类型:(1)直接芳基化反应;(2)基于σ-键或π-键的芳炔插入反应;(3)芳炔参与的三组分反应.相比于发展较为成熟的直接芳基化反应和基于σ-键或π-键的芳炔插入反应,芳炔参与的三组分反应机理尚不清楚,相关的综述也较为少见.为了科研工作者方便查阅、了解芳炔参与的三组分反应,对近年来芳炔参与的芳基化三组分反应研究进展进行综述.     

钯催化偶联-消去法合成芳基末端炔的研究进展

钯催化偶联-消去法合成芳基末端炔的研究进展;芳炔;偶联反应;钯催化剂;合成;综述     

金属镍催化炔基铝与炔溴高效合成对称1,3-二炔化合物

1,3-二炔类化合物是一类重要的有机合成中间体,被广泛应用于药物化学、有机合成及材料科学中.在室温条件下,以乙二醇二甲醚(DME)为溶剂,炔基溴(1 mmol)与炔基铝试剂(1.5 mmol)在Ni(acac)2(5 mol%)/DPPE(10 mol%)催化下进行偶联反应,以中等至优秀的收率得到了多种1,3-二炔烃类化合物.该反应体系对于带不同种类的功能基团的芳炔基铝试剂及炔基溴均有很好的催化活性.而且对于大位阻的α-萘炔及杂环2-噻吩炔也有较好的催化效果.该反应体系简单、催化效率高,不需要其它共催化剂.     

Recyclable Transition Metal Catalysis using Bipyridine-Functionalized SBA-15 by Co-condensation of Methallylsilane with TEOS

Well-defined recyclable Pd- and Rh-bipyridyl group-impregnated SBA-15 catalysts were prepared for C−C bond coupling reaction and selective hydrogenation reactions, respectively. These SBA-15 derived ligands for the catalysts were prepared by direct and indirect co-condensation method using bipyridyl-linked methallylsilane. This indirect method, involving methoxysilane generated from methallylsilane shows higher loading efficiency of transition metal catalysts on SBA-15 than the direct use of methallylsilane.     

A "green" route to perylene dyes: direct coupling reactions of 1,8-naphthalimide and related compounds under mild conditions using a "new" base complex reagent, t-BuOK/DBN.

The direct coupling reactions of 1,8-naphthalimide compounds efficiently occurred at 130 or 170 degrees C without the intervention of the leuco form dyes in the presence of base complex reagent, t-BuOK/1,5-diazabicyclo[4.3.0]non-5-ene (DBN), to give the corresponding perylene dyes in good yields with > 95% purities. A possible mechanistic speculation for these oxidative coupling reactions is briefly discussed.     

Pinacol Coupling Reactions Catalyzed by Active Zinc

The facile carbon-carbon bond formation is a forever goal and indispensable tool in organic synthesis1. Metal-mediated coupling reactions as highly efficient processes are always a major focus of directed synthesis2. Pinacol coupling reactions have been recognized to be efficient and selected alternatives for preparing several kinds of compounds3, not to mention those can be as versatile tools for preparing building blocks or exerted on synthesizing natural products in several key steps4. The …     

Efficient Pd-Catalyzed Direct Coupling of Aryl Chlorides with Alkyllithium Reagents

Organolithium compounds are amongst the most important organometallic reagents and frequently used in difficult metallation reactions. However, their direct use in the formation of C−C bonds is less established. Although remarkable advances in the coupling of aryllithium compounds have been achieved, Csp²−Csp³ coupling reactions are very limited. Herein, we report the first general protocol for the coupling or aryl chlorides with alkyllithium reagents. Palladium catalysts based on ylide-substituted phosphines (YPhos) were found to be excellently suited for this transformation giving high selectivities at room temperature with a variety of aryl chlorides without the need for an additional transmetallation reagent. This is demonstrated in gram-scale synthesis including building blocks for materials chemistry and pharmaceutical industry. Furthermore, the direct coupling of aryllithiums as well as Grignard reagents with aryl chlorides was also easily accomplished at room temperature.     

Cobalt-catalyzed cross-coupling reactions

In the last few years, we and other groups have demonstrated that economical cobalt salts can advantageously replace expensive and toxic catalysts for cross coupling reactions. These cobalt-catalyzed reactions have considerably extended the range of functionalized compounds. A variety of sensitive functional groups can be tolerated in these coupling reactions and various organic compounds RX could be involved (R = alkyl, alkynyl, aryl, allyl and X = halides: F, Cl, Br, I and even triflates). Here, we describe our contributions in this area for the preparation of a broad range of functionalized compounds from organometallic species or by direct cross-coupling.     

Simple instrument for titrimetry without visual indicators. Gasometric titrations: Argentometry

Several argentometric determinations have been worked out to show that the gasometric titration method is applicable not only to acid-base and redox reactions, but also to precipitation and complex-formation reactions. The processes reported allow the direct and indirect determination of iodide and cyanide, as well as the direct titration of silver ion in soluble and slightly soluble silver salts.     

Vibrational contributions to indirect spin-spin coupling constants calculated via variational anharmonic approaches

Zero-point vibrational contributions to indirect spin-spin coupling constants for N2, CO, HF, H2O, C2H2, and CH4 are calculated via explicitly anharmonic approaches. Thermal averages of indirect spin-spin coupling constants are calculated for the same set of molecules and for C2X4, X = H, F, Cl. Potential energy surfaces have been calculated on a grid of points and analytic representations have been obtained by a linear least-squares fit in a direct product polynomial basis. Property surfaces have been represented by a fourth-order Taylor expansion around the equilibrium geometry. The electronic structure calculations employ density functional theory, and vibrational contributions to indirect spin-spin coupling constants are calculated employing vibrational self-consistent-field and vibrational configuration-interaction methods. The performance of vibrational perturbation theory and various approximate variational calculations are discussed. Thermal averages are computed by state-specific and virtual vibrational self-consistent-field methods.     

Catalytic applications of transition-metal complexes bearing diphosphinidenecyclobutenes (DPCB)

The preparation and characterization of sterically protected diphosphinidenecyclobutenes bearing two two-coordinate phosphorus atoms are described from the viewpoint of the development of a novel type of bidentate ligand for transition-metal complexes. They form complexes with group 6 metals such as chromium, molybdenum and tungsten, group 8 metals such as ruthenium, group 10 metals such as palladium and platinum, and group 11 metals such as copper and gold. Some of them can be used as catalysts for synthetic reactions such as cross-coupling of the Sonogashira type, Suzuki-Miyaura coupling, Ullmann coupling, Kosugi-Migita-Stille coupling, cyanation, polymerization of ethylene, dehydrogenative hydrosilylation of ketones, hydroamination of 1,3-butadienes, and direct alkylation or amination of allylic alcohols of Tsuji-Trost reactions.     

Untersuchung der kinetik von azokupplungs-reaktionen mittels direkter injektions-enthalpiemetrie

The present paper deals with the application of direct injection enthalpimetry (DIE) in the study of the kinetics of azo coupling reactions. On the example of the coupling of diazotized aniline-4-sulphonic acid with 1,8-dihydroxynaphthalene-3,6-disulphonic acid, it was verified that the rate constants determined using DIE are comparable with those determined using spectrophotometry. Advantages result from the application of DIE in the study of the kinetics of azo coupling reactions.