Sonogashira Reaction Of Aryl Halides Research Articles

Palladium(II) complexes containing sterically bulky O, N donor ligands: Synthesis, characterization and catalytic activity in the Suzuki-Miyaura and Sonogashira coupling reactions

A new class of palladium(II)1-(arylazo)naphtholate complexes of the type [Pd(L1-4)2] containing sterically bulky O, N donor functionalized arylazo ligands has been synthesized. These palladium(II) complexes were characterized by elemental analysis and spectral (FT-IR, UV–Vis, 1H NMR and 13C NMR) studies. The molecular structure of the Palladium(II) complexes [Pd(L1)2] and [Pd(L2)2] were established by X-ray crystallography. These complexes were found to efficiently catalyze the Suzuki-Miyaura coupling of arylboronic acids and aryl halides, and the Sonogashira reaction of aryl halides and phenylacetylene in DMF and i-PrOH media to afford the corresponding C–C coupling products in high yields.

Copper(I) complex covalently anchored on graphene oxide as an efficient and recyclable catalyst for Sonogashira reaction

In this study, the organosilane‐functionalized graphene oxide as a stabilizer was prepared by a facile one‐step silylation approach. [Cu(PPh3)3Cl] complex was successfully immobilized onto the graphene oxide surface through coordination interaction with organosilane ligand spacers. The supported catalyst showed enhanced catalytic performance toward Sonogashira reaction of aryl halides with phenylacetylene in water solvent compared with the homogeneous analogues, and it could be readily recycled and reused several times without discernible loss of its activity.

Visible-light-enhanced photocatalytic Sonogashira reaction over silicon carbide supported Pd nanoparticles

Sonogashira reaction of aryl halides with terminal alkynes can be realized by a visible-light-driven heterogeneous catalytic route using silicon carbide supported Pd nanoparticles as the catalyst under copper-, and ligand-free conditions. Under the irradiation of visible light, the photo-generated electrons excited in SiC can quickly transfer to Pd nanoparticles through the Mott-Schottky contact, and make them electron-rich. The electrons of Pd particles become energetic by absorbing the energy of visible light, and then transfer to halogen atoms to facilitate the cleavage of carbon-halogen bond in aryl halides. The final carbon-carbon formation is achieved by the substitution reaction and reductive elimination processes.

A Green Approach for Copper-Free Sonogashira Reaction of Aryl Halides with Phenylacetylene in the Presence of Nano-Pd/Phosphorylated Silica (SDPP/Pd0)

Silicadiphenyl phosphinite (SDPP) is used as the solid support for the generation of nano SDPP/Pd(0) from PdII as pre-catalyst. This nano catalyst was used for the efficient copper-free Sonogashira reaction of aryl halides in PEG-200 as a solvent. The nano Pd(0) that can be used as pre-prepared or as in situ-generated catalyst exhibited excellent reactivity and stability in the Sonogashira cross-coupling reactions with different aryl iodides, bromides, and also chlorides. This heterogeneous catalyst can be easily recovered and reused in several runs. The use of PEG as solvent and K2CO3 as inorganic base together with the heterogeneous nature of the reaction can be considered as green conditions for this reaction.

Diphenylphosphorylated PEG (DPPPEG) as a new support for generation of nano-Pd(0) as catalyst for carbon–carbon bond formation via copper-free Sonogashira and homocoupling reactions of aryl halides in PEG

In this study, synthesis and application of diphenylphosphorylated PEG200 (DPPPEG200) are described. Herein, we report a very simple procedure for the preparation of DPPPEG200 as a stable solid through the reaction of PEG200 with ClPPh2. This compound was used as a very suitable ligand for the in situ generation of nano-Pd(0) particles through its reaction with PdCl2 as a pre-catalyst. Isolation of this catalyst is very simple through addition of diethyl ether to the reaction mixture and centrifugations. Full characterization of the nano-Pd(0)/DPPPEG200 was performed by XRD spectra, UV–Vis spectra, and also by TEM image. This nano-complex was used as an efficient catalyst for copper-free Sonogashira and homocoupling reactions of aryl halides. The sonogashira reaction of aryl halides was conducted at 80 °C in PEG. However, the homocoupling reaction was performed at 100 °C for aryl iodides and activated aryl bromides and at 130 °C for deactivated aryl bromides and aryl chlorides in PEG. The catalyst was recovered and recycled for four consecutive runs.

Synthesis and characterization of Schiff base complex of Pd(II) supported on superparamagnetic Fe3O4@SiO2 nanoparticles and its application as an efficient copper- and phosphine ligand-free recyclable catalyst for Sonogashira–Hagihara coupling reactions

Superparamagnetic nanoparticles functionalized with Schiff base complex of Pd (II) were simply synthesized by a two-step method. The catalyst was characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS),vibrating sample magnetometry (VSM), Fourier transform infrared (FT-IR), and N2 adsorption–desorption isotherm analysis. Also, its Pd content was determined by Inductively Coupled Plasma (ICP) analyzer. The immobilized palladium complex was used as an efficient catalyst for copper- and phosphine ligand-free Sonogashira reaction of aryl halides with phenylacetylene. This catalyst shows notable advantages such as simplicity of operation, excellent yields, short reaction times, heterogeneous nature, easy magnetically work up and recyclability.

Chelidamic acid functionalized stimuli-responsive hydrogel supported-palladium catalyst for copper-free Sonogashira reaction in aqueous media

A thermo and pH-responsive hydrogel (PNIPAM-co-PPAP) was synthesized via free radical polymerization of N-isopropylacrylamide (NIPAM) and potassium 4-(acryloyloxy) pyridine-2, 6-dicarboxylate (PAP) in mixed solvents of water and tetrahydrofuran. SEM micrographs revealed that the hydrogel was macroporous and the pores within the matrixes were interconnected. The chelidamic acid functionalized PNIPAM-co-PPAP hydrogel exhibited excellent capacity to anchor palladium (II) and the resulting material showed well catalytic activity for copper-free Sonogashira reaction of aryl halides with phenylacetylene in aqueous media. The reactions proceeded well with 0.1mol% of Pd (II) catalyst, due to the good dispersion of Pd2+ in the macroporous structure as well as the enrichment of reactants within hydrogel under reaction conditions. Through the reversibly swelling/deswelling, the PNIPAM-co-PPAP hydrogel-immobilized Pd (II) catalyst could be easily recovered by simple method. Furthermore, the PNIPAM-co-PPAP /Pd catalyst exhibited good recyclability and could be recycled six times without remarkable loss in catalytic activity.

Palladium complexes derived from N,N-bidentate NH-iminophosphorane ligands: synthesis and use as catalysts in the Sonogashira reaction

The addition of primary amines to the C=C bond of diphenylalkenyl iminophosphoranes yielded a new subtype of N,N-bidentate ligands bearing N=P(V)-C-C-NH backbones. These donor ligands reacted with PdCl(2)(COD) to give the corresponding σN,σN-palladium complexes containing secondary amino groups, bearing an intrinsically chiral nitrogen atom, and iminophosphorane units. These new complexes have been fully characterized by the use of spectroscopic techniques and X-ray crystallography. The comparison of the data extracted from their solution NMR spectra with their solid state structures demonstrated the conformational stability of their six-membered chelate ring and also the configurational stability of the chiral nitrogen atom, thus ruling out an arm-off racemization process. The addition of the chiral, racemic α-methylbenzylamine to the prochiral P-alkenyl iminophosphoranes yielded mixtures of the two expected diasteroisomeric ligands in low diastereoisomeric ratios. One of these mixtures was resolved into their components, each one in turn giving rise to a pair of diasteromeric palladium complexes epimeric at the amino nitrogen atom. One selected example of the new complexes efficiently catalyzes the copper- and amine-free Sonogashira reaction of aryl halides with acetylenes.

Heterogeneous Suzuki and copper-free Sonogashira cross-coupling reactions catalyzed by a reusable palladium(II) complex in water medium

An efficient heterogeneous Pd(II) azo complex catalyst for Suzuki and Sonogashira cross-coupling reaction has been developed. The catalyst showed an excellent activity for these reactions in water medium under aerial conditions. A new polystyrene anchored Pd(II) azo complex has been synthesized and characterized. The present Pd(II) azo complex behaves as a very efficient heterogeneous catalyst in the Suzuki coupling and Sonogashira coupling reaction in water medium. Aryl halides, coupled with phenylboronic acids (Suzuki–Miyaura reaction) or terminal alkyne (Sonogashira reaction), smoothly afford the corresponding cross-coupling products in excellent yields (83–100% yield for Suzuki reaction and 68–96% yield for Sonogashira reaction of aryl halides) under phosphine-free reaction conditions in the presence of polystyrene anchored Pd(II) azo complex catalyst in water medium. Furthermore, the catalyst has shown good thermal stability and recyclability. This polymer-supported Pd(II) catalyst could be easily recovered by simple filtration of the reaction mixture and reused for more than six consecutive trials without a significant loss of its catalytic activity.

ChemInform Abstract: Sonogashira Reaction of Aryl Halides with Terminal Alkynes Catalyzed by Cobalt Hollow Nanospheres.

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Sonogashira Reaction of Aryl Halides with Terminal Alkynes Catalyzed by Cobalt Hollow Nanospheres

Sonogashira reaction catalyzed by cobalt hollow nanospheres has been developed. Coupling of alkynes with aryl iodide or aryl bromide in the presence of potassium carbonate, triphen­ylphosphine, and cuprous iodide provides the corresponding products with moderate to good yields, which reveals obvious advantages such as low-cost catalyst, the recyclability of the catalyst, and simple experimental operation.

A Copper‐ and Amine‐Free Sonogashira Reaction of Aryl Halides Catalyzed by 1,3,5‐Triaza‐7‐phosphaadamantane Palladium Systems.

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Copper- and ligand-free Sonogashira reaction catalyzed by palladium in microemulsion

An oil-in-water microemulsion containing PdCl 2 and NaOH can be used as an effective catalyst system for rapid copper- and ligand-free Sonogashira reaction of aryl halides and phenylacetylene. Excellent yield of the Sonogashira reaction catalyzed by 0.5 mol% palladium could be achieved within 5 min. The types of base have an intense influence on the reaction. The reaction rate was increased with increased aqueous content in the microemulsions, and dispersed palladium nanoparticles can be in situ formed without other reductants.

A Copper- and Amine-Free Sonogashira Reaction of Aryl Halides Catalyzed by 1,3,5-Triaza-7-phosphaadamantane Palladium Systems

The monomeric complex [Pd(dmba)Cl(PTA)] [dmba = N,C-chelating 2-(dimethylaminomethyl)phenyl; PTA = 1,3,5-triaza-7-phosphaadamantane] has been obtained and its crystal structure has been established by X-ray diffraction. Conditions for an efficient copper- and amine-free catalyzed Sonogashira reaction of aryl bromides and chlorides with terminal alkynes by [Pd(dmba)Cl(PTA)] and Pd(OAc)2/PTA have been developed. It is worthwhile noting that a relatively low palladium catalyst loading has been employed.

Sonogashira Reaction of Aryl Halides with Propiolaldehyde Diethyl Acetal Catalyzed by a Tetraphosphine/Palladium Complex.

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Sonogashira reaction of aryl halides with propiolaldehyde diethyl acetal catalyzed by a tetraphosphine/palladium complex

All- cis-1,2,3,4-Tetrakis(diphenylphosphinomethyl)cyclopentane/[PdCl(C 3H 5)] 2 efficiently catalyzes the Sonogashira reaction of propiolaldehyde diethyl acetal with a variety of aryl bromides and chlorides. A minor electronic effect of the substituents of the aryl bromide was observed. Similar reaction rates were observed in the presence of activated aryl bromides such as 4-trifluoromethylbromobenzene and deactivated aryl bromides such as bromoanisole. Turnover numbers up to 95,000 can be obtained for this reaction. Even aryl chlorides and heteroarylbromides or chlorides have been successfully alkynylated with this catalyst. Moreover, a wide variety of substituents on the aryl halide such as fluoro, trifluoromethyl, acetyl, benzoyl, formyl, nitro, dimethylamino or nitrile are tolerated.

Sonogashira Cross‐Coupling Reactions Catalysed by Copper‐Free Palladium Zeolites

AbstractA heterogeneous copper‐free [Pd(NH3)4]2+/(NH4)Y catalyst was employed to achieve the heterogeneous Sonogashira reaction of aryl halides with terminal alkynes. Several reaction parameters like solvent, base and temperature were evaluated. When optimised, the coupling reaction of bromobenzene with phenylacetylene gave a 45% yield of diphenylacetylene within 3 h using only 1 mol % Pd. This catalyst was successfully applied to the coupling reaction of a range of aryl iodides and bromides: aryl iodides and activated aryl bromides gave almost quantitative yields and non‐activated aryl bromides led to reasonable yields (20% to 45%). This heterogeneous [Pd(NH3)4]2+/(NH4)Y catalyst was shown to be efficient, stable towards leaching and recyclable for the copper‐free Sonogashira reaction.

The Sonogashira Reaction in Water via an Amphiphilic Resin‐Supported Palladium‐Phosphine Complex under Copper‐Free Conditions.

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The Sonogashira Reaction in Water via an Amphiphilic Resin-supported Palladium-Phosphine Complex under Copper-free Conditions

The Sonogashira reaction of aryl halides with terminal alkynes was catalyzed by an amphiphilic polystyrene-poly(ethylene glycol) (PS-PEG) resin-supported palladium-phosphine complex in water to give the corresponding aryl-substituted alkynes in high yields under copper-free conditions. Reaction of o-iodophenol with terminal alkynes under Sonogashira conditions gave benzofuran derivatives in one step.