Suzuki Reaction Of Aryl Halides Research Articles

Urchin-like double-shelled Pd–PdO/ZnO hollow sphere as an efficient catalyst for the Suzuki-Miyaura reaction

In recent years, the modification of metal oxides with noble metals to decrease the loading amount of expense of noble metal catalyst and amend the stability of nanocatalyst in chemical reactions has attracted significant attention. Here in this study, the urchin-like double-shelled Pd–PdO/ZnO hollow sphere is successfully prepared by using a simple hydrothermal method and carbon sphere as a hard template. The structure of the catalyst was confirmed by using field-emission scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, energy-dispersive X-ray spectroscope, and BET. The total amount of palladium particles on ZnO was determined by induced coupled plasma analysis. The prepared catalyst gave high catalytic activity for the Suzuki reaction of aryl halides to afford biphenyls under milder conditions. Furthermore, the stability and reusability of catalyst were investigated, and all of the data proved that urchin-like double-shelled Pd–PdO/ZnO hollow sphere could be recycled five times without marked loss of activity.

Polymeric microsphere-loaded palladium-iminodiacetic acid complex as an efficient and easily recycled catalyst for Suzuki reaction in ionic liquid

Core-crosslinked shelled-core microspheres of poly(styrene-co-methyl acrylic acid) (PS-co-PMAA), with cores rich in PS and the shell rich in PMAA, were synthesized by one-stage soap-free emulsion polymerization. A palladium (Pd)-iminodiacetic acid (IDA) complex catalyst is loaded on the shell of the PS-co-PMAA microsphere, which results in the advantage of high dispersion degree and, therefore, high activity. The resultant polymeric microspheres catalyst systems are then applied to catalyze the Suzuki reaction of aryl halides with phenylboronic acid in an ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]). Our catalyst systems are proved to be efficient and active for both aryl bromides and aryl iodides. Compared to traditional Pd(Ph3)4 catalyst, the PS-co-PMAA-IDA-Pd catalyst used here affords higher yield of Suzuki reaction at even lower catalyst concentration. In addition, our polymeric-microsphere based catalytic system can be easily recycled at least four times with high activity in ionic [bmim][BF4] liquid.

Synthesis of Substituted Biarylmethanol via Ferrocenyloxime Palladacycles Catalyzed Suzuki Reaction of Chlorophenylmethanol in Water

Alcohols are of great importance as cheap and readily available organic materials for the preparation of many pharmaceutical products and fine chemicals. In addition, alcohols as electrophiles instead of alkyl halides in C-C (N) bonds forming reactions are particularly attractive because the process produces only water as byproduct. In spite of the existence of many synthetic routes, there are limited reports involving biarylmethanols. The palladium-catalyzed Suzuki reaction is an extremely efficient method for the construction of biaryl compounds. Among various Pd catalysts, palladacycles are one of the most active catalysts for the coupling reactions. From the economical and environmental points of view, employing readily accessible aryl chlorides and the use of water as a solvent in this reaction offer many advantages. However, there have been a few reports which demonstrated that palladacycles catalyzed Suzuki reaction of limited aryl chlorides in water. To our knowledge, only two accounts has been reported concerning the Suzuki of 4-chlorophenylmethanol in organic solvent. Recently, we have developed a cationic cyclopalladated ferrocenylpyrimidine catalyzed Suzuki reaction of aryl halides and 4-(hydroxymethyl)phenylboronic acid for the synthesis of substituted biarylmethanols in water. However, substrates are limited to the aryl bromides and activated aryl chlorides. To date, there is no report that investigates the Suzuki reaction of chlorophenylmethanol in water. As a continuation of our interest in the synthesis of biarylmethanols, we have prepared a new phosphine adduct of palladacycle 2 from the reaction of cyclopalladated ferrocenyloxime dimer 1 with commercially available 2-dicyclohexylphosphanyl-2'-(N,Ndimethylamino) biphenyl (DCPAB) (Scheme 1) and developed a practical method for the synthesis of biarylmethanols by the Suzuki reaction of chlorophenylmethanol and arylboronic acids in water. Complex 2 is airand moisture-stable, both in solid state and in solution. It was fully characterized by elemental analysis, IR, NMR and ESI-MS. In comparison with the corresponding frequencies of the free ferrocenyloxime, the C=N absorptions of 2 has been shifted to low values (1599 cm), indicating that the N atom is coordinated to palladium. The H NMR spectrum of 2 exhibits more signals than expected, and the P NMR appears two singlets at δ 65.54 and 67.15 ppm, suggesting the existence of isomers in solution. A similar phenomenon was also found in the H NMR

Hydrotalcite-supported palladium nanoparticles as catalysts for the Suzuki reaction of aryl halides in water

A simple protocol for the Suzuki reaction of aryl halides with phenylboronic acid is proposed. The catalyst used consists of Pd(0) nanoparticles supported on an Mg/Al hydrotalcite. The catalyst was prepared and characterized in this work for the first time. Supported nanoparticles were obtained by depositing a Pd(II) salt onto the support and subsequently reducing it to Pd(0). The greatest novelties of the synthetic process are the use of a hydrogen donor (cyclohexene) to reduce the palladium precursor salt and that of water as solvent in the Suzuki reaction. Biphenyl conversions in the Suzuki reaction of phenylboronic acid with iodobenzene, bromobenzene and chlorobenzene were all excellent, and quantitative yields obtained within a very short time. Even fluorobenzene provided excellent results improving on many reported values for chelated Pd homogeneous catalysts. No homocoupling reaction was detected; also, although homogeneous and heterogeneous catalysis coexist, the catalyst can be recovered for reuse with no loss of activity.

ChemInform Abstract: Suzuki—Miyaura Cross‐Coupling Reactions in Water Using in situ Generated Palladium(II)—Phosphazane Complexes.

AbstractThe catalyst generated in situ from Pd(OAc)2 and LIG shows good activity in the Suzuki reaction of aryl halides (I) with arylboronic acids (II).

Catalytic Activity of a Dimeric Palladacycle of 2-Phenylaniline in Suzuki and Heck Cross-coupling Reactions

A dimeric NC-palladacycle of 2-phenylaniline was applied in the Suzuki reaction of aryl halides and the Heck reaction of methyl acrylate and styrene with phenylboronic acid. This palladacycle was found to be effective catalyst for the Suzuki and Heck cross-coupling reactions which could be carried out in the undried solvent under air.

ChemInform Abstract: A Comparative Suzuki Reaction of Aryl Halides Using a New Dimeric Orthopalladated Complex under Conventional and Microwave Irradiation Conditions.

AbstractA new catalytic system for a rapid Suzuki cross‐coupling reaction is developed.

A comparative Suzuki reaction of aryl halides using a new dimeric orthopalladated complex under conventional and microwave irradiation conditions

The cross‐coupling reaction between phenylboronic acid and various types of aryl halides (Suzuki reaction) was carried out using a catalytic amount of a new phosphine‐based catalyst under microwave irradiation. The reaction conditions were optimized and results showed that, by application of this catalytic system, N‐methyl‐2‐pyrrolidone as the solvent and potassium carbonate as the base, reactions could be completed in a short reaction time with high to excellent yields. Copyright © 2012 John Wiley & Sons, Ltd.

Cyclopalladated complexes of 2-phenylaniline and their catalytic activity in Suzuki and Heck reactions under mild conditions

A series of palladium complexes bearing monodentate and bidentate ligands were applied in the Suzuki reaction of aryl halides and the Heck reaction of styrene with phenylboronic acid. The complexes were found to be effective catalysts for these reactions affording the cross-coupled products in moderate to excellent yields.

A novel thermo and pH-double sensitive hydrogel immobilized Pd catalyst for Heck and Suzuki reactions in aqueous media

A novel Hydrogel (1) was prepared from N-isopropylacrylamide, 4-vinylpyridine and potassium acrylate by free radical cross-linking polymerization. Hydrogel (1) showed both thermosensitivity and pH-sensitivity, and exhibited high swelling capacity in water. Because Hydrogel (1) has porous structure in its network and good loading performance with Pd2+, it was used as “microreactor” for immobilization of metal nanoparticles. We chose Heck and Suzuki reaction of aryl halides in water as test reaction to probe the catalytic activity of such Hydrogel (1) supported palladium catalyst. As a result, the Hydrogel (1)-Pd (II) catalyst exhibited good catalytic activity in both Heck and Suzuki reactions. Moreover, the Hydrogel (1)-Pd (II) catalyst was easily recovered and recycled. The reuse experiments showed that it was recycled six times without obviously losing of catalytic activity.

An Efficient and Recyclable Fluorous Palladium Catalyst for the Room-Temperature Suzuki Reaction

A new fluorous nano-palladium catalyst was prepared and characterized. The catalytic activity of the catalyst has been evaluated for the Suzuki reaction of aryl halides and aryl boronic acids to afford the corresponding products in high yields. The reaction proceeded smoothly in the presence of 0.1 mol% catalyst in EtOH/H2O at room temperature. In addition, the catalyst could be recovered by fluorous liquid–liquid separation and reused for three times without significant loss of activity. The Suzuki reaction catalyzed by a new fluorous nano-palladium catalyst to afford the products in high yields at room temperature has been described. The catalyst can be recovered by fluorous liquid–liquid separation and reused for several times without significant loss of activity.

Green synthesis of fluorinated biaryl derivatives via thermoregulated ligand/palladium-catalyzed Suzuki reaction

Fluorinated compounds have attracted considerable attention in pharmaceuticals, agrochemicals and material science due to their unique physical properties. This paper reports an efficient and environmentally benign protocol for the Suzuki reaction of aryl halides with fluorinated arylboronic acids over a thermoregulated ligand/palladium catalyst using water as sole medium, affording a variety of fluorinated biaryls, including fluorinated liquid crystals, in excellent yields. The catalyst could be recycled four times with high activity. The active catalyst was proved to be a palladium/ligand complex via a mercury-poisoning test.

Very Fast, Ligand‐Free and Aerobic Protocol for the Synthesis of 4‐Aryl‐Substituted Triphenylamine Derivatives

AbstractA fast, convenient and ligand‐free protocol for the synthesis of a series of 4‐aryl‐substituted triphenylamine derivatives by a palladium‐catalysed aerobic Suzuki reaction of aryl halides with [4‐(diphenylamino)phenyl]boronic acid in aqueousiPrOH is described. Importantly, both aryl bromides and heteroaryl halides afforded good to excellent yields under mild conditions.

Palladium(II) Complexes Containing 2,6-Bis(Imino)Pyridines: Synthesis, Characterization, Thermal Study, and Catalytic Activity in Suzuki Reactions

A series of palladium complexes: [(Pydim)PdCl](PdCl3) (Pydim (1): pyridine-2,6-diimine) have been synthesized from palladium dichloride and the corresponding pydim. The Pd (II) complexes have been used as catalyst in the Suzuki reaction of aryl halides. Moreover, thermal behaviors of palladium complexes have been studied in nitrogen atmosphere using TG/DTG and DTA techniques. The values of activation energy Ea, and reaction order n, the entropy change Δ S*, enthalpy change Δ H#, and Gibbs free energy change Δ G# of the thermal decomposition were calculated by means of several methods based on the single heating rate.

Dodecylsulfate Anion Embedded Layered Double Hydroxide Supported Nanopalladium Catalyst for the Suzuki Reaction

Abstract The dodecylsulfate anion (DS − ) embedded layered double hydroxide (LDH) supported nanopalladium catalyst (LDH-DS-Pd 0 ) is a novel phosphine free recyclable heterogeneous catalytic system for palladium catalyzed Suzuki coupling reactions and has been prepared for the first time. The intercalation of DS − changed the interlayer spacing of LDH from a microsize to a mesosize (2.9 nm) range, which favors the diffusion of average sized organic molecules. The Pd 0 clusters obtained from the reduction of PdCl 4 2– -interlayered LDH were intercalated between the LDH layers and hence the growth of Pd 0 clusters was effectively hindered by the limited space created by the intercalation of DS − . This lipophilic catalyst was highly efficient in promoting the Suzuki reaction of aryl halides with phenylboronic acid. As a heterogeneous nanocatalyst, LDH-DS-Pd 0 could be reused five times without significant loss of catalytic activity.

Suzuki reaction catalysed by a PC sp3P pincer Pd(II) complex: Evidence for a mechanism involving molecular species

{ Cis-1,3-bis[(di- tert-butylphosphino)methyl]cyclohexyl}palladium(II)trifluoroacetate ( 1) acts as a precatalyst for the Suzuki reaction of aryl halides with phenylboronic acid in the absence or presence of mercury to give the product in modest to reasonably good yields. The reaction was monitored by 31P- and 1H NMR spectroscopy in a stepwise fashion, concluding that complex 1 reacts with activated boronic acids in the first reaction step to yield the corresponding phenyl complex 2. Complex 2 thereafter generates the Suzuki cross-coupling product upon addition of aryl halide. This shows that (PCP)Pd complexes, in addition to the previously demonstrated Pd(0)/Pd(II) mechanism, can mediate cross-coupling reactions using molecular species in a non-zero oxidation state.

MCM-41-supported bidentate phosphine palladium(0) complex as an efficient catalyst for the heterogeneous Suzuki reaction

MCM-41-supported bidentate phosphine palladium(0) complex was conveniently synthesized from commercially available and cheap γ-aminopropyltriethoxysilane via immobilization on MCM-41, followed by reacting with diphenylphosphinomethanol and palladium chloride and then the reduction with hydrazine hydrate. The powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the title palladium complex. It was found that this complex is a highly active catalyst for the heterogeneous Suzuki reaction of aryl halides with arylboronic acids and can be reused many times without loss of activity.

PEG-Supported Dipyridyl Ligand for Palladium-Catalyzed Suzuki and Suzuki-Type Reactions in PEG and Aqueous Media

An air- and water-stable PEG-supported bidentate nitrogen ligand is prepared and its applications in the palladium-catalyzed Suzuki reaction of aryl halides with arylboronic acids in PEG and Suzuki-type reaction of aryl halides with sodium tetraphenylborate in aqueous media are reported. The homogeneous catalyst system is environmentally friendly and offers the advantages of high activity, reusability and easy separation.

Synthesis of novel palladacycles and their application in Heck and Suzuki reactions under aerobic conditions.

[reaction: see text] Design and synthesis of a novel family of furancarbothioamide-based palladacycles are reported herein. These palladacycles are thermally stable, not sensitive to air or moisture, and are applied effectively in the Heck reaction of aryl halides with terminal olefins and in the Suzuki reaction of aryl halides with arylboronic acids. These reactions were performed under aerobic conditions, leading to turnover numbers (TONs) up to 1 x 10(5).