Mizoroki Heck Cross-coupling Reactions Research Articles

Polyaniline-Supported Palladium(II)-Schiff Base Complex as Efficient Catalyst for Mizoroki-Heck Cross-Coupling Reaction

Mizoroki-Heck cross-coupling reaction of 4-bromoacetophenone with methyl acrylate were investigated as a model system of heterogeneous reaction in order to evaluate the performance of polyaniline supported N,N’-bis(3,5-di-tert-butylsalicylidene)propane-1,3-diaminepalladium(II) complex as catalyst. The reactions were carried out in both N,N-dimethylacetamide (DMAc) and water-DMAc mixed solvent. The performances of the catalyst in both media are comparable, giving more than 90 % conversion after 24 hours of reaction with 100 % selectivity and high isolated product yields of cinnamic esters were obtained. The used of mixed solvent gave more advantages such as less organic solvent was required and an enhanced recyclability in which the supported catalyst could be reusable at least four times without noticeable decrease in the product conversion. The properties of the catalyst was characterized by various techniques such as FTIR spectroscopy, TG-DTA, AAS, BET surface area, XRD and FESEM.

Aryl–Phenyl Scrambling in Intermediate Organopalladium Complexes: A Gas‐Phase Study of the Mizoroki–Heck Reaction

The intramolecular aryl-phenyl scrambling reaction within palladium-DPPP-aryl complex (DPPP=1,3-bis(diphenylphosphino)propane) ions was analyzed by state-of-the-art tandem MS, including gas-phase ion/molecule reactions. The Mizoroki-Heck cross-coupling reaction was performed in the gas phase, and the intrinsic reactivity of important intermediates could be examined. Moreover, linear free-energy correlations were applied, and a mechanism for the scrambling reaction proceeding via phosphonium cations was assumed.

Supported Pd nanoparticles on Mn-based metal–organic coordination polymer: Efficient and recyclable heterogeneous catalyst for Mizoroki–Heck cross coupling reaction of terminal alkenes

Supported palladium nanoparticles on Mn-carboxylate coordination polymer (Pd/MnBDC) were prepared using solution impregnation method. This new catalyst was characterized by XRD, SEM, TEM, EDX, XPS, FTIR and TGA analysis. The Pd/MnBDC exhibits efficient catalytic activity for the Mizoroki–Heck coupling reaction between iodobenzene and either aromatic or aliphatic terminal alkenes and reuses up to four runs without significant loss of activities.

Palladium nanoparticles supported on triazine functionalised mesoporous covalent organic polymers as efficient catalysts for Mizoroki–Heck cross coupling reaction

A material based on palladium nanoparticles supported on nitrogen rich mesoporous covalent organic polymers exhibiting excellent catalytic activity towards Mizoroki–Heck cross coupling reaction.

A new hierarchically porous Pd@HSQ monolithic catalyst for Mizoroki–Heck cross-coupling reactions

Palladium nanoparticles are embedded in hierarchically porous hydrogen silsesquioxane monoliths by on-site reduction to prepare a reusable catalyst for Mizoroki–Heck reactions.

A Robust, Moisture- and Air-Stable Phosphine Mono-Ylide Palladacycle Precatalyst: A Simple and Highly Efficient System for Mizoroki–Heck Reactions

A palladacycle phosphine mono-ylide complex was identified as an efficient catalyst system for the Mizoroki–Heck cross-coupling reactions of aromatic or aliphatic olefins with a variety of aryl bromides and chlorides, including those containing electron-donating or electron-withdrawing substituents. The reactions, which proceeded in moderate to excellent yields, required relatively low loadings of palladium (10 ppm) and were performed under aerobic conditions. High catalyst activities with turnover frequencies of up to 20,000 h–1 were observed at 130 °C.

Cryptand-22 as an Efficient Ligand for the Palladium-Catalyzed Mizoroki–Heck Reaction under Air

An efficient catalytic system for the Mizoroki–Heck cross-coupling reaction was developed based on the air- and heat-stable palladium(II) chloride–cryptand 22 complex. The complex is a highly active catalyst for coupling of aryl iodides, bromides, or chlorides with various olefins.

Preoxidated polyacrylonitrile fiber mats supported copper catalyst for Mizoroki–Heck cross-coupling reactions

Porous preoxidated polyacrylonitrile (PAN) fiber mats, which was prepared by electrospinning and then followed by thermal treatment, has been used for the immobilization of copper catalyst. FT-IR/ATR spectra and XRD pattern show that the linear polymer structure of the PAN fiber mat can be converted into the ladder molecular structure at the high temperature. The morphology of the copper catalyst supported on the preoxidated PAN fiber mats was examined by scanning electron microscopy (SEM). The catalytic activity and stability of the fiber mat supported copper catalyst have been evaluated using the Mizoroki–Heck cross-coupling reaction of aryl iodides with different acrylates. It was found that the catalytic activities of fiber mat supported copper catalyst could be significantly promoted by addition of small amount of additives, such as ethylene glycol.

Efficient PEPPSI-Themed Palladium N-Heterocyclic Carbene Precatalysts for the Mizoroki–Heck Reaction

Two sets of six PEPPSI (pyridine enhanced precatalyst preparation, stabilization, and initiation) themed palladium complexes of amide-functionalized N-heterocyclic carbenes [PdBr2(NHC)(Py)], where NHC = 1-acetamido-3-R-imidazolin-2-ylidene, 1-acetamido-3-R-benzimidazolin-2-ylidene and Py = pyridine, were prepared. Solid-state structures of all these complexes were determined by single-crystal X-ray diffraction methods. All complexes under scrutiny were found to adopt a trans arrangement with square-planar geometry. These complexes showed excellent catalytic activity toward the Mizoroki–Heck cross-coupling reaction of aryl chlorides and styrene. Benzimidazole-derived complexes exhibited better catalytic activity than imidazole-based complexes. Formation of palladium nanoparticles in the reaction mixture was evidenced by dynamic light scattering and transmission electron microscopy studies and a mercury poisoning experiment, suggesting the possible involvement of palladium nanoparticles in the catalytic rea...

The use of palladium nanoparticles supported on graphene oxide in the Mizoroki-Heck reaction

We have developed a convenient single-step method for producing palladium nanoparticles on the surface of graphene oxide by reducing palladium chloride with NaBH4. According to transmission electron microscopy data, palladium nanoparticles have a spheroidal shape; their sizes are 6–8 nm. The tests of immobilized palladium nanoparticles have shown that they exhibit high activity in the Mizoroki-Heck cross-coupling reaction.

Synthesis and characterization of 1-phenyl-3-alkylbenzimidazol-2-ylidene salts and their catalytic activities in the Heck and Suzuki cross-coupling reactions

The synthesis and characterization of 1-phenyl-3-alkyl-substituted carbene precursors that were prepared from 1-phenyl substituted benzimidazole and various alkyl halides are reported. The new benzimidazolium salts (1a–e) were characterized by 1H NMR, 13C NMR, FT-IR spectroscopic methods and elemental analyses. New in situ generated palladium-benzimidazolium complexes were tested for catalytic activity in the Mizoroki-Heck and Suzuki-Miyaura cross-coupling reactions.

Scalable synthesis of catalysts for the Mizoroki–Heck cross coupling reaction: palladium nanoparticles assembled in a polymeric nanosphere

Palladium nano-spheres 160 nm in diameter, as an assembly of uniform 5 nm nanoparticles, are accessible using a facile one step method under continuous flow on a spinning disc with hydrogen gas as the reducing agent. The stable colloidal system is an effective catalyst for the Mizoroki–Heck reaction, as established for the reaction between several aryl halides and n-butyl acrylate, and can be readily recycled without a change in their catalytic activity.

Mizoroki-Heck cross-couplings of 2-acetyl-5-bromobenzofuran and aryl halides under microwave irradiation

Mizoroki-Heck cross-coupling reactions of 2-acetyl-5-bromobenzofuran as well as activated and deactivated aryl bromides with various olefins were investigated under both thermal as well as microwave irradiating conditions in open air using water solvent.

Highly Air-Stable Anionic Mononuclear and Neutral Binuclear Palladium(II) Complexes for C−C and C−N Bond-Forming Reactions

The short-bite aminobis(phosphonite), PhN{P(-OC10H6(mu-S)C10H6O-)}2 (2), containing a mesocyclic thioether backbone is synthesized by either treating PhN(PCl2)2 with 2 equiv of thiobis(2,2'-naphthol) or reacting chlorophosphite (-OC10H6(mu-S)C10H6O-)PCl (1) with aniline in the presence of a base. Treatment of 2 with an equimolar amount of Pd(COD)Cl2 in the presence of H2O affords a P-N-P-bridged and P,S-metalated binuclear complex, [PhN(P(-OC10H6(mu-S)C10H6O-)-kappaP)2Pd2Cl2{P(-OC10H6(mu-S)C10H6O-)(O)-kappaP,kappaS}2] (3), whereas the same reaction with 2 equiv of Pd(COD)Cl2 in the presence of H2O and Et3N produces the mononuclear anionic complex [{(-OC10H6(mu-S)C10H6O-)P(O)-kappaP,kappaS}PdCl2](Et3NH) (5). By contrast, reaction of 2 with 2 equiv of Pd(COD)Cl2 and H2O in the absence of Et3N gives the hydrogen phosphonate coordinated complex [{(-OC10H6(mu-S)C10H6O-)P(OH)}PdCl2] (4) which converts to the anionic complex in solution or in the presence of a base. Compound 2 on treatment with Pt(COD)X2 (X = Cl or I) afforded P-coordinated four-membered chelate complexes [PhN(P(-OC10H6(mu-S)C10H6O-)-kappaP)2PtX2] (6 X = Cl, 7 X = I). The crystal structures of compounds 2, 3, 5, and 7 are reported. Compound 3 is the first example of a crystallographically characterized binuclear palladium complex containing a bidentate bridging ligand and its hydrolyzed fragments forming metallacycles containing a palladium-phosphorus sigma bond. All palladium complexes proved to be very good catalysts for the Suzuki-Miyaura and Mizoroki-Heck cross-coupling and amination reactions with excellent turnover numbers (TON up to 1.46 x 105 in the case of the Suzuki-Miyaura reaction).

An inexpensive and highly stable ligand 1,4-bis(2-hydroxy-3,5-di-tert-butylbenzyl)piperazine for Mizoroki–Heck and room temperature Suzuki–Miyaura cross-coupling reactions

A bulky, inexpensive and simple bidentate ligand 1,4-bis(2-hydroxy-3,5-di-tert-butylbenzyl)piperazine (1) has been synthesized and characterized. The palladium catalyst was formed by combination of 1 with [Cl2Pd(COD)] in a ratio of 1:1, tested in the Suzuki–Miyaura and Mizoroki–Heck cross-coupling reactions. Coupling of a variety of aryl bromides with phenylboronic acid using methanol as solvent at room temperature, or at 60°C, gave generally high yields of coupled products. Coupling of aryl chlorides with organoboron reagent at 110°C in DMF afforded good yields of biaryls under aerobic conditions. This non-phosphorus, air and moisture stable catalyst also displays good activity for Mizoroki–Heck coupling reaction in methanol at 60°C with various aryl chlorides and bromides.

Microwave-assisted Suzuki–Miyaura and Heck–Mizoroki cross-coupling reactions of aryl chlorides and bromides in water using stable benzothiazole-based palladium(II) precatalysts

The catalytic activity of benzothiazole-based Pd(II)-complexes was evaluated in Suzuki–Miyaura and Heck–Mizoroki C–C cross-coupling reactions of aryl chlorides and bromides with olefins and arylboronic acids both under thermal as well as microwave irradiation conditions in water. The factors affecting the optimization of such reactions as well as the reusability of the Pd-precatalysts are studied.

Phosphine-Free Palladium Catalyzed Mizoroki−Heck Reaction Using Hydrazone as a Ligand

Glyoxal bishydrazones 1 and pyridyl-hydrazone 2b were prepared and examined as a ligand for the Mizoroki-Heck cross-coupling reaction of aryl halides and olefin. We found that PdCl2(MeCN)2/hydrazone ligand 1e was a phosphine-free efficient catalyst system for a variety of substrates to produce the Mizoroki-Heck coupling products in good yields.

Comparison and Evaluation of Two Immobilisation Techniques for Task Specific Onium Salts (TSOS) in Mizoroki-Heck Cross Coupling Reactions

A coating consisting of an ionic liquid (1,3-butylmethylimidazolium hexafluorophosphate [BMIM][PF6]) was deposited on silica gel as well as on a new polyvinylimidazolium phase and treated with a task specific onium salt (TSOS). The activity and stability of both immobilised Pd-species were studied and compared in Mizoroki-Heck cross coupling reactions.