Coupling Reactions Of Aryl Halides Research Articles

The coupling reactions of aryl halides and phenols catalyzed by palladium and MOP-type ligands

Palladium-catalyzed coupling reactions of aryl halides and phenols are described employing the bulky and electron-rich MOP-type ligands. When K3PO4 was used as base and toluene as solvent, the catalyst system exhibited high efficiency for the coupling reaction of the activated aryl halides. When NaH was used as base and o-xylene as solvent, unactivated aryl halides can be used as substrates.

2-(diphenylphosphino)pyridine platinum (I) and palladium (I) complex as an efficient binuclear catalyst for Suzuki-Miyaura coupling reaction in water under mild reaction conditions

Binuclear complex of platinum (I) and palladium (I) showed superior activity in Suzuki-Miyaura coupling reaction of aryl halides with arylboronic acids compared to the sole palladium or platinum species. The catalyst showed good tolerance in water and coupling reactions were performed in water as a green solvent. Aryl iodides were reacted at room temperature and the reactions of aryl bromides were performed at 60 °C.

ChemInform Abstract: Simple and Efficient Phosphine‐Free Pd(OAc)2 Catalyzed Urea Accelerated Suzuki—Miyaura Cross‐Coupling Reactions in iPrOH—H2O at Room Temperature.

Abstract A simple, efficient, and less expensive protocol for the phosphine-free Suzuki–Miyaura cross-coupling reactions of aryl halides with different aryl boronic acids in iPrOH–H2O under aerobic conditions has been developed. The mixture of Pd(OAc)2 and urea catalyzes the Suzuki–Miyaura cross-coupling of a variety of aryl halides with aryl boronic acids at room temperature, giving generally high yields even under low catalytic loads. The effect of solvent, base, and catalyst loading on the coupling reaction of aryl halide with arylboronic acid is also described.

A highly active palladium(II)–bis(oxazoline) catalyst for Suzuki–Miyaura, Mizoroki–Heck and sonogashira coupling reactions in aqueous dimethylformamide

An efficient catalytic system based on a new palladium–bis(oxazoline) (Pd-BOX-1) complex has been developed. The complex Pd-BOX-1 adopts a legless chair‐type structure where the distorted square planar [PdN2Cl2] moiety and the benzene ring spacer represent the seat and the chair back, respectively. The catalytic activity of Pd-BOX-1 has been investigated in dimethylformamide–water under aerobic and mild conditions in Suzuki–Miyaura coupling reactions of arylboronic acids with aryl iodides, aryl bromides and aryl chlorides, Mizoroki–Heck coupling reactions of aryl halides with styrene derivatives, and Sonogashira coupling reactions of aryl halides with terminal alkynes. A wide range of functional groups as substituents on the arylboronic acids and aryl halides were considered. Pd-BOX-1 demonstrates exceptional air and moisture stability. Of note, the catalyst system based on Pd-BOX-1 shows high recycling ability in Suzuki–Miyaura coupling reactions in dimethylformamide–water without any loss in catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.

Biaryl thioether synthesis via CuI catalyzed dominothiolation of aryl halides in the presence of DMAP as ligand

An improved protocol has been developed for the synthesis of symmetrical biaryl sulfides via a dominothiolation reaction using CuI as catalyst in the presence of DMAP as ligand. The coupling reaction of aryl halides was carried out in the presence of 5mol% of CuI and 20mol% of DMAP using thiourea as sulfur transfer agent. High yields of corresponding product were obtained by carrying out the reaction in DMSO at 120°C.

Simple and efficient phosphine-free Pd(OAc)2 catalyzed urea accelerated Suzuki–Miyaura cross-coupling reactions in iPrOH–H2O at room temperature

A simple, efficient, and less expensive protocol for the phosphine-free Suzuki–Miyaura cross-coupling reactions of aryl halides with different aryl boronic acids in iPrOH–H2O under aerobic conditions has been developed. The mixture of Pd(OAc)2 and urea catalyzes the Suzuki–Miyaura cross-coupling of a variety of aryl halides with aryl boronic acids at room temperature, giving generally high yields even under low catalytic loads. The effect of solvent, base, and catalyst loading on the coupling reaction of aryl halide with arylboronic acid is also described.

Palladium-loaded Renewable Polymer as a Green Heterogeneous Catalyst for Cross-coupling Reactions under Microwave Irradiation

A new palladium catalyst was prepared by immobilising ligand 2, 2′-dipyridylamine on the backbone of an acidic rosin polymer from gum rosin, on to which palladium(II) was bound via coordination. The catalyst at a low loading of 0.2 mol% was found to be highly effective for Suzuki–Miyaura coupling reactions of aryl halides and arylboronic acids under microwave irradiation in the presence of 1 equiv. of Na2CO3, affording excellent yields of the corresponding biaryls. Moreover, the catalyst exhibited very good recyclability over three cycles.

ChemInform Abstract: tBu3P‐Coordinated 2‐Phenylaniline‐Based Palladacycle Complexes as Precatalyst for Pd‐Catalyzed Coupling Reactions of Aryl Halides with Polyfluoroarenes by a C—H Activation Strategy.

AbstractThe reaction is applicable to a broad scope of functionalized aryl bromides, as well as aryl iodides, and chlorides to give high yields.

Polyaniline‐anchored palladium catalyst‐mediated Mizoroki–Heck and Suzuki–Miyaura reactions and one‐pot Wittig–Heck and Wittig–Suzuki reactions

A polyaniline‐anchored palladium catalyst was prepared and screened for coupling reactions of aryl halides. The robust and recyclable catalyst was effective in Mizoroki–Heck and Suzuki–Miyaura reactions of aryl bromides and aryl iodides. The catalyst system was further employed for one‐pot Wittig–Heck and Wittig–Suzuki combinations to build conjugated compounds in good conversions. Copyright © 2014 John Wiley & Sons, Ltd.

Palladium complexes of 2-formylpyridine thiosemicarbazone and two related ligands: Synthesis, structure and, spectral and catalytic properties

Thiosemicarbazones of 2-formylpyridine, 2-aceylpyridine and 2-benzoylpyridine, abbreviated in general as HL-R (where H depicts the acidic hydrogen and R the fragment (R=H, Me and Ph) linked to the imine-carbon) react with [Pd(PPh3)2Cl2] in refluxing ethanol in the presence of triethylamine to afford complexes of the type [Pd(L-R)(PPh3)]Cl (1, R=H; 2, R=Me, 3, R=Ph). Structures of the complexes 1 and 3 have been determined by X-ray crystallography, and the structure of complex 2 has been optimized by DFT. In all three the thiosemicarbazone ligand binds to the metal center as a monoanionic tridentate NNS-donor forming two adjacent five-membered chelate rings, the triphenylphosphine occupies the fourth coordination site on palladium. Complexes 1–3 display intense absorptions in the visible and ultraviolet regions, which have been analyzed by TDDFT calculations. All the complexes are found to efficiently catalyze Suzuki, Heck and Sonogashira type C–C cross-coupling, and C–N coupling reactions of aryl halides with primary and secondary amines. All the catalytic reactions are found to proceed under ligand-free condition.

ChemInform Abstract: A New Recyclable/Reusable Ionic Liquid/LiCl System for Suzuki—Miyaura Cross Coupling Reactions.

Abstract Suzuki–Miyaura cross coupling reactions of aryl halides with aryl boronic acids were carried out in basic ionic liquids in the presence of lithium chloride as a promoter. The coupling reactions, carried out in the absence of base and ligand, proceed in good to excellent yields with easy product isolation and catalyst recycle.

A simple, efficient and recyclable catalytic system for carbon–sulfur coupling of aryl halides with thioacetamide

The carbon–sulfur coupling reaction of aryl halides with thioacetamide using an MCM-41-immobilized bidentate nitrogen copper(I) complex [MCM-41-2N-CuI] as an efficient heterogeneous catalyst is described. Developed catalytic system is found to be effective for the coupling reaction of aryl halides with thioacetamide providing moderate to high yield of diaryl sulfides. This heterogeneous copper catalyst exhibits higher activity than CuI and can be recovered by a simple filtration of the reaction solution and reused for at least 10 consecutive trials without any decreases in activity.

M(II) Schiff base complexes (M = zinc, manganese, cadmium, cobalt, copper, nickel, iron, and palladium) supported on superparamagnetic Fe3O4@SiO2 nanoparticles: synthesis, characterization and catalytic activity for Sonogashira–Hagihara coupling reactions

A series of magnetically separable catalysts consisting of Schiff base complexes of metal ions (Zn, Mn, Cd, Co, Cu, Ni, Fe and Pd) supported on superparamagnetic Fe3O4@SiO2 nanoparticles has been prepared. The structural features of the catalysts were characterized by XRD, FTIR, TEM, FE-SEM, DLS, VSM, UV–Vis, TGA, AFM and N2 adsorption–desorption. Some of the Fe3O4@SiO2/Schiff base complexes were found to be efficient catalysts for the Cu-free and the phosphine free Sonogashira–Hagihara coupling reaction of aryl halides and phenylacetylene. The catalysts are superparamagnetic, and thus could be easily separated by the utilization of an external magnetic field, and could be reused for six cycles without significant loss of activity.

N,N′-bis(2-pyridinecarboxamide)-1,2-benzene palladium complex as a new efficient catalyst for Suzuki–Miyaura coupling reaction under phosphane free conditions

In this article, palladium complex of N,N′-bis(2-pyridinecarboxamide)-1,2-benzene has been introduced as a new catalyst for the Suzuki–Miyaura coupling reaction of aryl halides in water. The catalyst is easily prepared from the reaction of Pd(OAc)2 and N,N′-bis(2-pyridinecarboxamide)-1,2-benzene ligand and has been characterized using 1H NMR, TGA, FT-IR, solid and liquid UV–Vis spectroscopy.

Pd immobilized on amidoxime-functionalized Mesoporous SBA-15: A novel and highly active heterogeneous catalyst for Suzuki–Miyaura coupling reactions

Herein we described the synthesis of a novel SBA-15/AO/Pd(II) nanocatalyst by grafting of amidoxime on SBA-15 and subsequent deposition of palladium chlorides. Prior to grafting of amidoxime (AO), the prepared [2-cyanoethyl]-functionalized Mesoporous SBA-15 through combining of 2-cyanoethyltriethoxysilane and SBA-15 was treated with hydroxylamine. The amidoxime grafted SBA-15 (SBA-15/AO) were then used as platform for in situ deposition of Pd complex. The materials were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), inductivity coupled plasma (ICP), nitrogen adsorption–desorption, and Fourier transform infrared (FTIR) spectroscopy. SBA-15/AO/Pd(II) are novel phosphine-free recyclable heterogeneous catalyst for Suzuki coupling reaction of aryl halides (I, Br, Cl) with phenylboronic acid to provide the corresponding products. These cross-coupled products were produced in excellent yields under mild conditions at extremely low palladium loading (∼0.2mol%) with perfect high turnover frequencies (TOFs). The heterogeneous catalyst can be readily recovered by simple filtration and reused six times with loss in its activity.

Metal-catalyzed reductive coupling reactions of organic halides with carbonyl-type compounds.

Metal-catalyzed reductive coupling reactions of aryl halides and (pseudo)halides with carbonyl-type compounds have undergone an impressive development within the last years. These methodologies have shown to be a powerful alternate strategy, practicality aside, to the use of stoichiometric, well-defined, and, in some cases, air-sensitive organometallic species. In this Minireview, the recent findings in this field are summarized, with particular emphasis on the mechanistic interpretation of the results and future aspects of this area of expertise.

Hybrid Pd/Fe3O4 nanowires: Fabrication, characterization, optical properties and application as magnetically reusable catalyst for the synthesis of N-monosubstituted ureas under ligand-free conditions

This paper reports the synthesis and use of Pd/Fe3O4 nanowires, as magnetically separable catalysts for ligand-free amidation coupling reactions of aryl halides with benzylurea under microwave irradiation. Then, the in situ hydrogenolysis of the products was performed to afford the N-monosubstituted ureas from good to excellent yields. This method has the advantages of high yields, simple methodology and easy work up. The catalyst can be recovered by using a magnet and reused several times without significant loss of its catalytic activity. The catalyst was characterized using the powder XRD, SEM, EDS and UV–vis spectroscopy. Experimental absorbance spectra was compared with results from the Gans theory.

A new recyclable/reusable ionic liquid/LiCl system for Suzuki–Miyaura cross coupling reactions

Suzuki–Miyaura cross coupling reactions of aryl halides with aryl boronic acids were carried out in basic ionic liquids in the presence of lithium chloride as a promoter. The coupling reactions, carried out in the absence of base and ligand, proceed in good to excellent yields with easy product isolation and catalyst recycle.

Polymer‐Supported Electron‐Rich Oxime Palladacycle as an Efficient Heterogeneous Catalyst for the Suzuki Coupling Reaction

AbstractVarious electron‐rich oxime palladacycle resins designed as heterogeneous catalysts were employed for the Suzuki coupling reaction of aryl halides with arylboronic acids. The electron‐richness of the oxime ligand was controlled by the substituted alkoxy groups. Evaluation based on the electronic effect of the catalysts revealed that the alkoxy‐substituted oxime palladacycle resins showed better catalytic activity than palladated Kaiser oxime resin in the Suzuki coupling reactions and that the catalytic activity of oxime palladacycle resins increased as the electron‐richness of oxime ligand increased. The most electron‐rich oxime palladacycle resin exhibited an excellent catalytic performance for the synthesis of both biaryl and heterobiaryl compounds, despite its heterogeneous system. As a practical application of the catalyst, a valsartan precursor was synthesized in high yield under mild conditions. The electron‐rich oxime resin could also be reused for up to 5 cycles while maintaining good catalytic activity in the Suzuki coupling reaction.magnified image

Nanosized palladium supported on diethylenetriamine modified superparamagnetic polymer composite microspheres: Synthesis, characterization and application as catalysts for the Suzuki reactions

Superparamagnetic polymer composite microspheres Fe3O4/P(GMA-AA-MMA) prepared by an emulsifier free emulsion polymerization using DPE as free radical control agent were used to support palladium nanoparticles. The magnetic catalyst can provide excellent reactivity in the Suzuki coupling reactions of aryl halides with phenylboronic acids under mild condition (at 80°C) in EtOH/H2O (1:1) mixture. Furthermore, the novel catalyst can be conveniently recovered by an external magnet field and reused at least five times without significant loss of its catalytic activity.