Reaction Of Aryl Halides Research Articles

New arylselanylpyrazole-copper catalysts: Highly efficient catalytic system for C[sbnd]Se and C[sbnd]S coupling reactions

We describe herein the use of arylselanylpyrazole–copper complexes as versatile catalysts for CSe and CS coupling reactions. The performance of these complexes for CSe reactions was investigated in chalcogenoacetylene synthesis. The reactions were carried out under mild and aerobic conditions and afforded selanylalkynes bearing a variety of electron-withdrawing and electron-donating groups. The performance of these catalysts for CS coupling was investigated through the reaction of aryl halides with thiols and products were obtained in moderate to excellent yields. A plausible mechanism for selenoacetylene synthesis is also suggested, and the 77Se NMR results show that these arylselanylpyrazole ligands act as hemilabile ligands. High-resolution mass spectrometry was used to investigate the intermediates and also to corroborate the proposed catalytic cycle.

Buchwald–Hartwig C–N cross coupling reactions catalyzed by palladium nanoparticles immobilized on thio modified-multi walled carbon nanotubes as heterogeneous and recyclable nanocatalyst

In current research, the multi walled carbon nanotubes was functionalized with mercapto-melamine groups by covalent grafting of f-CNT with ethylenediamine, cyanuric chloride and 2-mercaptoethanol for introducing mercapto functional groups on the surface of nanotube. Consequently, the thiolated MWCNTs were applied to deposing Pd nanoparticles. The results of FTIR, Raman spectroscopy, powder XRD, energy dispersive spectroscopy (EDS), wavelength-dispersive X-ray spectroscopy (WDX) and CHN analysis showed the successful synthesis of nanocatalyst. The scanning and transmission electron microscopes (SEM and TEM) were used to study the morphologies of the nanocatalyst. Moreover, the (MWCNTs/CC-SH/Pd) nanocatalyst was effectively applied in Buchwald–Hartwig C–N cross coupling reaction with wide variety of functionalized substrates. A variety of aryl amines were prepared through reaction of aryl halides (chloride, bromide and iodide) and amines in high yields. Remarkably, the new catalyst could be reused for six recycles without change in its catalytic activity.

Novel palladium nanoparticles supported on β‐cyclodextrin@graphene oxide as magnetically recyclable catalyst for Suzuki–Miyaura cross‐coupling reaction with two different approaches in bio‐based solvents

A novel nanocatalyst was designed and prepared. Initially, the surface of magnetic graphene oxide (M‐GO) was modified using thionyl chloride, tris(hydroxymethyl)aminomethane and acryloyl chloride as linkers which provide reactive C═C bonds for the polymerization of vinylic monomers. Separately, β‐cyclodextrin (β‐CD) was treated with acryloyl chloride to provide a modified β‐CD. Then, in the presence methylenebisacrylamide as a cross‐linker, monomers of modified β‐CD and acrylamide were polymerized on the surface of the pre‐prepared M‐GO. Finally, palladium acetate and sodium borohydride were added to this composite to afford supported palladium nanoparticles. This fabricated nanocomposite was fully characterized using various techniques. The efficiency of this easily separable and reusable heterogeneous catalyst was successfully examined in Suzuki–Miyaura cross‐coupling reactions of aryl halides and boronic acid as well as in modified Suzuki–Miyaura cross‐coupling reactions of N‐acylsuccinimides and boronic acid in green media. The results showed that the nanocatalyst was efficient in coupling reactions for direct formation of the corresponding biphenyl as well as benzophenone derivatives in green media based on bio‐based solvents. In addition, the nanocatalyst was easily separable, using an external magnet, and could be reused several times without significant loss of activity under the optimum reaction conditions.

Palladium(II) anchored on polydopamine coated-magnetic nanoparticles (Fe3O4@PDA@Pd(II)): A heterogeneous and core–shell nanocatalyst in Buchwald–Hartwig C–N cross coupling reactions

An efficient method was proposed to synthesize polydopamine (PDA)-coated Fe3O4 nanoparticles (Fe3O4@PDA). For the first time, effective deposition of Pd complex is explained by using Fe3O4@PDA as a core–shell magnetic coordinator and stabilizer agent. In this method, palladium ions were adsorbed on Fe3O4@PDA surfaces through immersion of the Fe3O4@PDA into a palladium plating bath. The structure, morphology and physicochemical features of the prepared particles were studied using various analytical methods including high resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma (ICP), thermogravimetric analysis (TGA) and FT-IR spectroscopy. Core–shell Fe3O4@PDA/Pd(II) nanoparticles showed excellent catalytic performance as a reusable nanocatalyst in Pd-catalyzed Buchwald–Hartwig CN cross coupling reaction. A variety of aryl amines were prepared through reaction of aryl halides (chloride, bromide and iodide) and amines in high yields. The catalyst can be recycled and reapplied up to six cycles with no considerable change in its catalytic activity.

CNC pincer palladium complex supported on magnetic chitosan as highly efficient and recyclable nanocatalyst in C─C coupling reactions

A stable and durable magnetic chitosan‐supported triazine‐bridged bisimidazolium pincer palladium catalyst (Fe3O4@ChC@CNC‐PdII) was synthesized and characterized using various techniques. The Fe3O4@ChC@CNC‐PdII complex displayed high activity in the production of substituted biaryls via the cross‐coupling reactions of aryl halides with arylboronic acids. Also, this catalyst could be simply recovered from the reaction mixture and reused in 13 consecutive runs with no loss of its catalytic activity.

Chloromethylated polystyrene supported copper (II) bis–thiazole complex: Preparation, characterization and its application as a heterogeneous catalyst for chemoselective and homoselective synthesis of aryl azides

This work deals the synthesis of aryl azides catalyzed by heterogeneous copper (II) complex of 3,5–bis (2–benzothiazolyl) pyridine, [Cu (II)(BTP)(OTf)2], immobilized on chloromethylated polystyrene, [Cu (II)(BTP)(OTf)2]@CMP. The prepared catalyst was characterized by different analytical techniques such as X‐ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (SEM), energy dispersive X–ray spectroscopy (EDX), elemental analysis, and FT‐IR and UV–Vis spectroscopic methods. This catalytic system showed excellent activity in the synthesis of aryl azides by the reaction of aryl halides with sodium azide in the presence of catalytic amounts of [Cu (II)(BTP)(OTf)2]@CMP. Moreover, this unique catalyst could be recovered easily and reused several times without any considerable loss of its catalytic activity.

Encapsulation of palladium chloride using 2‐formylbenzoic acid supported by Fe3O4 nanoparticles modified with SiO2 and propylamine, its characterization and its application for Suzuki coupling reaction

A magnetically separable heterogeneous nanocatalyst, Fe3O4@SiO2(CH2)3N―CH―Ar@Pd(0), was simply prepared and characterized using various techniques. The catalytic activity of this nanocatalyst was evaluated via the Suzuki–Miyaura cross‐coupling reaction of aryl halides with phenylboronic acid under various experimental conditions such as kind of base, solvent and temperature. This nanocatalyst is completely magnetically recoverable because of the superparamagnetic behaviour of Fe and can be reused with sustained selectivity and activity.

Iron‐catalyzed cross‐coupling reaction: Heterogeneous palladium and copper‐free Heck and Sonogashira cross‐coupling reactions catalyzed by a reusable Fe(III) complex

An interesting silica‐supported iron catalyst was successfully prepared and demonstrated as an efficient heterogeneous catalyst for cross‐coupling reactions of aryl halides. The as‐prepared nanocatalyst was well characterized and found to be highly efficient in Heck reaction under mild and sustainable conditions (water as solvent at 80 °C in short reaction time). Furthermore, the obtained catalyst was used as an efficient, inexpensive and green heterogeneous catalyst for Sonogashira cross‐coupling reactions of various aryl iodides and provided the corresponding products with moderate to good yields. This phosphine, copper and palladium‐free catalyst was simply recovered from the reaction mixture and recycled five times without substantial decrease in its catalytic activity.

Magnetic iron oxide nanoparticles/K2S: a simple and scale-up method for the direct synthesis of symmetrical disulfides from aryl halides

A simple, one-pot, efficient and novel protocol has been developed for direct synthesis of symmetrical organic disulfides by domino reaction of aryl halides and K2S in the presence of magnetic Fe3O4 nanoparticles as a readily available, highly efficient and recyclable catalyst. A variety of diaryl disulfides can be obtained in good-to-excellent yields up to 98%.

Recent Advances in the Application of the Heck Reaction in the Synthesis of Heterocyclic Compounds: An Update

Background: The reaction of aryl halides or vinyl halides with activated alkenes in the presence of Palladium-catalyst along with a base for the formation of the C-C bond is called the Heck reaction. This reaction has been employed extensively in the synthesis of heterocyclic compounds. Methodology: We have highlighted these applications in 2010. Conclusion: This review aims to cover the recent application of the Heck reaction in the synthesis of heterocyclic compounds during a period from 2010 to 2017. Keywords: Heck reaction, heterocyclic compounds, Pd, palladium, carbon-carbon bond formation, catalysis.

A Novel Method for the Direct Synthesis of Symmetrical and Unsymmetrical Sulfides and Disulfides from Aryl Halides and Ethyl Potassium Xanthogenate

An efficient and new method for the synthesis of disulfides and sulfides via the reaction of aryl halides with ethyl potassium xanthogenate in the presence of MOF-199 is described. O-Ethyl-S-aryl ­carbonodithioate has a key role as an intermediate in this procedure; it was converted into symmetrical diaryl disulfides in DMF. Additionally, this could be applied to the synthesis of unsymmetrical aryl alkyl(aryl′) disulfides by the reaction with S-alkyl(aryl) sulfurothioates (Bunte salts) as well as unsymmetrical aryl alkyl(aryl′) sulfides in DMSO.

A novel heterogeneous nanocatalyst: 2‐Methoxy‐1‐phenylethanone functionalized MCM‐41 supported Cu(II) complex for C‐S coupling of aryl halides with thiourea

An environmentally friendly copper‐based catalyst supported on 2‐Methoxy‐1‐phenylethanone functionalized MCM‐41 was prepared and characterized by FT‐IR, FE‐SEM, TEM, XRD, EDX, BET and ICP techniques. The catalyst was applied for the C−S cross‐coupling reaction of aryl halides with thiourea. Corresponding products were produced in good yields in aerobic conditions. The catalyst could be recovered and recycled for several times.

Preparation and Characterization of Ni‐Modified Graphene Oxide Complex as an Efficient Catalyst for the Synthesis of Sulfides via Reaction of Arylhalides with S8 or Thiourea

In this work, complex of Ni‐modified graphene oxide was prepared and characterized using FT‐IR spectroscopy, SEM, XRD, TGA and ICP‐OES techniques. This compound used as an efficient and recoverable catalyst for the C–S coupling reaction using sulfur‐transfer reagents (S8 or thiourea). The catalyst was easily separated using a simple filtration and reusable without significant loss of their catalytic efficiency.

Kryptofix 5 as an inexpensive and efficient ligand for the palladium‐catalyzed Mizoroki‐Heck reaction

A novel complex of PdCl2 with a multidentate cryptand ligand, Kryptofix 5, has been prepared and characterized by various techniques including 1H‐ and 13C NMR spectroscopy, Fourier transform infrared (FT‐IR), Raman, ultraviolet and visible (UV‐VIS) spectroscopy, inductively coupled plasma (ICP), CHN elemental and energy dispersive X‐ray analysis (EDX). This heat‐ and air‐stable complex was utilized as a highly active catalyst for the Mizoroki‐Heck reaction of aryl halides with various olefins. Interestingly, it was found that aryl bromides as well as aryl iodides were efficiently cross‐coupled with terminal alkenes at 130 °C in 10 min. Furthermore, the least reactive aryl chlorides reacted with styrene to obtain the desired products in acceptable yields.

One‐Pot Domino Synthesis of Diarylalkynes/1,4‐Diaryl‐1,3‐diynes by [9,9‐Dimethyl‐4,5‐bis(diphenylphosphino)xanthene] (Xantphos)–Copper(I) Iodide–Palladium(II) Acetate‐Catalyzed Double Sonogashira‐Type Reaction

AbstractThe low loading combination of the complex [9,9‐dimethyl‐4,5‐bis(diphenylphosphino)xanthene] (Xantphos)copper(I) iodide and simple ligand‐free palladium(II) acetate was found to be efficient for the domino synthesis of diarylalkynes by the reaction of aryl halides with trimethylsilylethynylene or bis(trimethylsilyl)acetylene in a single‐step procedure. The unsymmetrical diarylalkynes can be obtained through a one‐pot two‐step approach. The reactions of aryl bromides with 1,4‐bis(trimethylsilyl)butadiyne also furnished the corresponding 1,4‐diaryl‐1,3‐diynes in a similar fashion. This route to diarylalkynes and 1,4‐diaryl‐1,3‐diynes is complementary to previously reported synthetic procedures.magnified image

Copper-catalyzed synthesis of 2-aminophenyl benzothiazoles: a novel approach.

A novel, convenient and efficient protocol for the construction of various 2-aminophenyl benzothiazoles by domino intra- and intermolecular C-N cross-coupling reactions of arylisothioureas with aryl iodides using an inexpensive, air stable and readily available copper catalyst is described. The arylisothioureas were obtained from thiourea via copper promoted desulfurization followed by nucleophilic substitution. In addition, the reactivity of arylhalides and the reaction mechanism have also been studied. The protocol features operational simplicity and a broad substrate scope.

Synthesis of Ni(II)-3,5-dichloro-2-hydroxybenzenesulfonyl chloride supported SBA-15 and its application as a nanoreactor catalyst for the synthesis of diaryl sulfides via reaction of aryl halides with thiourea or S8

In the present work, SBA-15 mesoporous grafted with 3-(trimethoxysilyl)-1-propanethiol as a linker and subsequently reacted by 3, 5-dichloro-2-hydroxybenzenesulfonyl chloride. Then to obtain the new catalyst Ni(II) was supported on functionalized SBA-15 by using Ni(NO3)2 as Ni(II) source. The Ni/SBA-15 catalyst was characterized with SEM, EDS, ICP, XRD, TGA, FT-IR and N2 sorption–desorption analysis. The key advantages of this heterogeneous catalyst are inexpensive, short reaction times, excellent yields, recovery and reusability.

Halide Abstraction Competes with Oxidative Addition in the Reactions of Aryl Halides with [Ni(PMen Ph(3-n) )4

Density functional theory (DFT) calculations have been used to study the oxidative addition of aryl halides to complexes of the type [Ni(PMenPh(3−n))4], revealing the crucial role of an open‐shell singlet transition state for halide abstraction. The formation of NiI versus NiII has been rationalised through the study of three different pathways: (i) halide abstraction by [Ni(PMenPh(3−n))3], via an open‐shell singlet transition state; (ii) SN2‐type oxidative addition to [Ni(PMenPh(3−n))3], followed by phosphine dissociation; and (iii) oxidative addition to [Ni(PMenPh(3−n))2]. For the overall reaction between [Ni(PMe3)4], PhCl, and PhI, a microkinetic model was used to show that our results are consistent with the experimentally observed ratios of NiI and NiII when the PEt3 complex is used. Importantly, [Ni(PMenPh(3−n))2] complexes often have little, if any, role in oxidative addition reactions because they are relatively high in energy. The behaviour of [Ni(PR3)4] complexes in catalysis is therefore likely to differ considerably from those based on diphosphine ligands in which two coordinate Ni0 complexes are the key species undergoing oxidative addition.

Synthesis of (Ph3P)2PdX2 complexes and their catalytic activity for Heck reaction involving aryl halide and acrylate

Two palladium complexes, (Ph3P)2PdBr2 and (Ph3P)2PdI2, were synthesized by a new method and their structures were confirmed by NMR, elemental analysis and X-ray crystallography. The catalytic activity of the two palladium complexes was evaluated in Mizoroki-Heck cross-coupling reaction of aryl halide with acrylate, the results show that they all have high catalytic activity to many different substrates.

Palladium stabilized on poly and mono sulfonamide ligands as novel, simple, effective, and recyclable nano catalysts for C–C cross-coupling reactions

Poly and mono sulfonamide ligands were successfully used for the stabilization of palladium nanoparticles. The prepared nano catalysts that appeared to be heterogeneous and novel were characterized with various analytical tools. To establish the catalytic activity of the prepared catalysts, they were used in the Suzuki–Miyaura and Sonogashira–Hagihara coupling reactions of aryl halides under low palladium loading conditions. The catalysts showed good stability and could be recovered and reused for seven reaction cycles without significant loss of catalytic activity.