Palladium‐Catalysed Direct Cross‐Coupling of Organolithium Reagents with Aryl and Vinyl Triflates

A palladium‐catalysed cross‐coupling of organolithium reagents with aryl and vinyl triflates is presented. The reaction proceeds at 50 or 70 °C with short reaction times, and the corresponding products are obtained with moderate to high yields, with a variety of alkyl and (hetero)aryl lithium reagents.     

LiCl-Accelerated Nickel Catalyzed Cross-Coupling of Aryl Tosylates with the Aryl Grignard Reagents

Russian Journal of General Chemistry - A mild coupling reaction catalyzed by Ni(acac)2-L4 has been studied. The catalyst acts efficiently in the reaction of biaryl coupling between various...     

缺电子芳香三氟甲磺酸酯与胺的氯化锌配合物的交叉偶联反应

采用新型的有机胺氯化锌配合物作为缺电子芳香三氟甲磺酸酯转化成芳胺的试剂,研究发现反应可以在二甲基亚砜和碳酸钾的作用下进行,无需隔氧、密封,也不必加入配体.提出了不同于经典SNAr过程的机理,并对生成的胺化产物进行了IR,MS和1H NMR表征.     

Cross-Coupling of Aryllithiums with Aryl and Vinyl Halides in Flow Microreactors

The use of Pd catalysts that contained a carbene ligand, such as PEPPSI-SIPr, speeded up the Murahashi coupling of ArLi with ArBr, by enabling its integration with the Br/Li exchange of ArBr with BuLi in flow. Space integration realized the rapid cross-coupling of two different ArBr substrates. However, the cross-coupling reaction with vinyl halides could not be achieved under similar conditions. Pd(OAc)₂ was an effective catalyst, and the space integration of the Br/Li exchange of ArBr with BuLi and the Murahashi coupling with vinyl halides was successfully achieved.     

铁催化下二芳基锌和芳基格氏试剂的二氟烷基化反应

随着医药、农药、材料等领域对含氟化合物日益增长的需求,发展向有机分子中直接引入氟原子和含氟基团的方法受到了化学家们的广泛重视.近些年来,过渡金属催化的氟烷基化反应,作为一种温和可控向有机分子引入含氟基团的策略得到了快速发展.与此同时,从反应的高效简洁和绿色温和性角度出发,发展廉价金属作为催化剂以及使用廉价易得的氟卤烷烃作为氟烷基试剂是非常具有吸引力的.本文以绿色低毒的Fe（acac）₃为催化剂,首次实现了铁催化下二芳基锌与α,α-二氟炔丙基溴的交叉偶联反应.该反应条件温和、原料廉价易得,产物可以放大到克量级制备,并能进行多种转化.此外,这一铁催化体系还可以实现芳基格氏试剂与二氟烷基溴代的偶联反应,为合成二氟烷基芳烃化合物提供了一种有效方法.初步的机理研究表明,该反应可能经历了单电子转移的自由基反应历程,偕二氟炔丙基自由基存在反应催化循环中.     

铁催化芳基格氏试剂的联芳交叉偶联的反应机理

利用密度泛函理论(DFT)计算研究了[Fe(MgBr)₂]催化的邻氯苯乙稀与溴代苯基镁反应生成联芳化合物的交叉偶联反应的机理. 研究了两个机理. 机理A包括三个基本步骤: (I) 氧化[Fe(MgBr)₂]生成[Ar-Fe(MgBr)],(II) 加成产生[Ar-(phenyl)-Fe(MgBr)₂], (III) 还原消除回到[Fe(MgBr)₂]. 机理B不形成[Ar-Fe(MgBr)]. 在第一步,溴代苯基镁在[Cl-Mg-Br]离解形成[Ar-Fe(MgBr)]之前直接进攻氧化加成后的中间体. 考虑溶剂效应后, 机理B优于机理A. 无论机理A还是机理B, 整个催化循环过程的决速步骤都是[Ar-(phenyl)-Fe(MgBr)₂]的还原消除再生催化剂[Fe(MgBr)₂]的步骤, 使用导体极化连续模型(CPCM)方法计算其在四氢呋喃溶剂中的吉布斯自由能(ΔG_sol)是82.98 kJ·mol^-1.     

Pd/Ni Co-catalyzed Selective Cross-Coupling of Aryl Bromides and Aryl Fluorosulfonates at Room Temperature

Multimetallic catalysis can effectively enhance the selectivity for the heterocoupling product over homocoupling products in cross-electrophilic couplings. We report the selective cross-coupling of aryl bromides with aryl fluorosulfonates via palladium and nickel cooperative catalysis for the synthesis of biaryls, which can be carried out at room temperature while having marvelous chemoselectivity. In addition, the reaction also has a good performance on the gram-scale reaction.     

Copper(II)-Mediated Dehydrogenative Cross-Coupling of Heteroarenes

Cu(OAc)(2)-mediated dehydrogenative cross-coupling between two heteroarenes has been realized in the absence of any other additive. A mechanism involving a formal Cu(II) to Cu(0) route by convergent disproportionation of the copper mediator is proposed and has been evidenced by copper mirror formation during the reaction. This synthetic protocol provides a concise and "green" access to unsymmetrical biheteroarenes bearing structural motifs of substantial utility in organic synthesis.     

Designing Cross-Coupling Reactions using Aryl(trialkyl)silanes

Organo(trialkyl)silanes have several advantages, including high stability, low toxicity, good solubility, easy handling, and ready availability compared with heteroatom-substituted silanes. However, methods for the cross-coupling of organo(trialkyl)silanes are limited, most probably because of their exceeding robustness. Thus, a practical method for the cross-coupling of organo(trialkyl)silanes has been a long-standing challenging research target. This article discusses how aryl(trialkyl)silanes can be used in cross-coupling reactions. A pioneering example is Cu^II catalytic conditions with the use of electron-accepting aryl- or heteroaryl(triethyl)silanes and aryl iodides. The reaction forms biaryls or teraryls. This design concept can be extended to Pd/Cu^II-catalyzed cross-coupling polymerization reactions between such silanes and aryl bromides or chlorides and to Cu^I-catalyzed alkylation using alkyl halides.     

A New Route to 6-Aryl-substituted 3,4-Dihydronaphthalene Derivatives via Pd (O)-Catalyzed Cross-Coupling Reaction of Aryl Zinc Chlorides with an Aryl Triflate

A procedure for the Pd (O)-catalyzed cross coupling of the triflate of 6-hydroxy-3,4-dihydronaphthalene-2-methylcarboxylate with various aryl zinc chlorides was developed, which represents an efficient approach to 6-aryl-substituted naphthalene derivatives.     

Copper(I)-Catalyzed Cross-Coupling of 1-Bromoalkynes with N-Heterocyclic Organozinc Reagents

Nitrogen-containing heterocycles represent the majority of FDA-approved small-molecule pharmaceuticals. Herein, we describe a synthetic method to produce saturated N-heterocyclic drug scaffolds with an internal alkyne for elaboration. The treatment of N,N-dimethylhydrazinoalkenes with Et₂Zn, followed by a Cu(I)-catalyzed cross-coupling with 1-bromoalkynes, results in piperidines and pyrrolidines with a good yield. Five examples are reported and a proposed mechanism for the Cu(I)-catalyzed cross-coupling is presented.     

Palladium-Catalyzed Cross-Coupling of Vinylalanes with Aryl Halides

Synthesis of tri-and tetrasubstituted olefins was achieved via palladium-catalyzed cross-coupling of vinylalanes with arylhalides.     

Synthesis,Structure, and Reactivity of 5-(Aryl)dibenzothiophenium Triflates

A synthetic protocol for the preparation of 5-(aryl)dibenzothiophenium salts starting from inexpensive dibenzothiophene S-oxide and simple arenes is reported. The scope of the method regarding the nature of the arene is evaluated, intermediates along the reaction sequence have been trapped, and side-reactions identified. In addition, the X-ray structures of a complete set of these salts are reported and their reactivities studied. Specifically, chemoselective Suzuki coupling is observed at the dibenzothiophenium in the presence of iodides.     

N‐Arylation of Diketopyrrolopyrroles with Aryl Triflates

A new methodology for the double N‐arylation of diketopyrrolopyrroles with aryl triflates has been developed. It is now possible to prepare diketopyrrolopyrroles bearing N‐substituents derived from naphthalene, anthracene and coumarin in two steps from commercially available phenols. This represents the first time arenes lacking strong electron‐withdrawing groups were inserted onto lactamic nitrogen atoms via arylation. The ability to incorporate heretofore unprecedented substituents translates to increased modulation of the resulting photophysical properties such as switching‐on/off solvatofluorochromism. TD‐DFT calculations have been performed to explore the nature of the relevant excited states. This new synthetic method made it possible to elucidate the influence of such substituents on the absorption and emission properties of tetraaryl substituted diketopyrrolopyrroles.     

Iron(II)‐Catalyzed Direct Cyanation of Arenes with Aryl(cyano)iodonium Triflates

A direct oxidative cyanation of arenes under Fe^II catalysis with 3,5‐di(trifluoromethyl)phenyl(cyano)iodonium triflate (DFCT) as the cyanating agent has been developed. The reaction is applicable to wide range of aromatic substrates, including polycyclic structures and heteroaromatic compounds.     

Nickel-Catalyzed Cross-Coupling of Ethyl Chlorofluoroacetate with Aryl Bromides

A combinatorial nickel-catalyzed monofluoroalkylation of aryl bromides with the industrial raw regent ethyl chlorofluoroacetate has been developed. The two key factors to successful conversion are the combination of nickel with readily available nitrogen and phosphine ligands and the using of a mixture of different solvents. Mechanistic investigations indicated a new zinc regent might generated in situ and be involved in the reaction process.     

Palladium-Catalyzed Cross-Coupling of 2,3-Naphthoxadisilole with Aryl Halides

Palladium-catalyzed cross-coupling between 2,3-naphthoxadisilole and aryl halides in the presence of tetrabutylammonium fluoride afforded 2-aryl naphthalenes. This is first report that oxadisilole served as a partner in the palladium-catalyzed cross-coupling reactions. The reaction mechanism was also studied.     

Halogen Selectivity in Nickel Salt-Catalyzed Cross-Coupling of Aryl Grignard Reagents with Bromochlorobenzenes a Novel Synthetic Method of Unsymmetrical Terphenyl

The reactions of aryl Grignard reagents with p- and m-bromochlorobenzenes catalyzed by non-ligated NiCl₂ give selectively chlorobiphenyl derivatives. By the stepwise reaction, an unsymmetrical terphenyl was synthesized in a good yield.     

2-吡唑啉-9-芳基邻菲咯啉镍配合物催化芳基卤化物和格氏试剂偶联反应的研究

4个基于2-吡唑啉-9-芳基邻菲咯啉（L¹-L⁴）镍配合物[NiCl₂L]（1-4）被开发用于芳基卤化物和格氏试剂偶联反应的研究,表现出良好的催化活性.对配合物（4）的结构进行了x-单晶衍射表征,分析发现中心金属镍为五配位的四方锥构型利于C-C偶联反应.讨论了配体空间位阻及反应条件对该偶联反应活性的影响,发现邻菲咯啉的9位位阻对催化活性影响更明显.