Heck Mizoroki Research Articles

Ligand-free Pd-catalyzed highly selective arylation of activated and unactivated alkenes via oxidative and reductive heck coupling.

In this work, an eco-friendly, green, efficient approach for oxidative and reductive Heck-Mizoroki (HM) reactions was developed, which offered acceptable yields from first-pass experiments. Mono-arylation was achieved without the use of ligands, directing groups, or prefunctionalized alkenes. Considering mild reaction conditions, good functional group compatibility, and great regioselectivity, the method can find broad applications in novel medicine and material development and discovery processes.

(Fe3O4@SiO2/GO–NH2–CoII NPs): A Novel and Efficient Nanomagnetic Heterogeneous Cobalt Catalysis in the Sonogashira and Heck–Mizoroki Coupling Reactions

(Fe3O4@SiO2/GO–NH2–CoII NPs): A Novel and Efficient Nanomagnetic Heterogeneous Cobalt Catalysis in the Sonogashira and Heck–Mizoroki Coupling Reactions

A palladium Schiff base complex covalently bonded to functionalized mesoporous MCM-41: a novel, green and highly efficient catalyst for Heck–Mizoroki and Suzuki–Miyaura cross-coupling reactions in water-medium

A palladium Schiff base complex covalently bonded to functionalized mesoporous MCM-41: a novel, green and highly efficient catalyst for Heck–Mizoroki and Suzuki–Miyaura cross-coupling reactions in water-medium

Imidazolium organometallic complex of palladium on Fe3O4 nanoparticles as selective and magnetically recoverable nanocatalyst for C‐C cross‐coupling reactions

The synthesis of an efficient heterogeneous nanocatalyst was prepared by the anchoring of palladium complex on the surface of an imidazolium‐based ionic liquid‐functionalized Fe3O4 (Pd‐imidazolium@Fe3O4 NPs). The nanocatalyst, Pd‐imidazolium@Fe3O4 NPs, was characterized by Raman, X‐ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), fourier transform infrared (FT‐IR), inductively coupled plasma (ICP), and vibrating sample magnetometer (VSM) techniques. The catalytic performance of this novel nanocatalyst was evaluated in the Heck––Mizoroki and Suzuki–Miyaura cross‐coupling reactions under mild conditions using PEG‐400 as a green and biodegradable solvent. The nanocatalyst exhibited high catalytic activity for both cross‐coupling reactions. Furthermore, this stable nanocatalyst can be easily removed and recovered from the reaction mixture and reused for at least eight consecutive cycles without a discernible decrease in the catalytic activity. Also, the recovered Pd‐imidazolium@Fe3O4 NPs was characterized by FT‐IR, XRD, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and atomic absorption spectroscopy techniques.

Pd–PEPPSI type complexes bearing unsymmetrical NHC ligand with phenyl‐substituted backbone: Highly efficient catalysts for Heck–Mizoroki and Suzuki–Miyaura cross‐coupling reactions

A series of air‐stable NHC–Pd–PEPPSI‐type complexes bearing unsymmetrical NHC ligand, with a phenyl group in its backbone, were synthesized in excellent yields (82%–94%). Air and moisture‐stable complexes were characterized by using 1H NMR, 13C NMR, FT‐IR spectroscopy, and HRMS techniques. Single‐crystal X‐ray diffraction method was used to determine the crystal and molecular structure of the complexes. The molecular structure adopts slightly distorted square planar geometry around the metal centre and was refined as an inversion twin. The complexes were screened for their catalytic activities in Heck–Mizoroki and Suzuki–Miyaura cross‐coupling reactions. Heck–Mizoroki reaction between the various aryl/hetaryl bromides and styrenes occurred in good to excellent yields in DMF in the presence of NaOAc as a base with low catalyst loadings (0.5%). The reactions also occur in aqueous media (DMF‐H2O) in high yields. The Suzuki–Miyaura reaction between various aryl/hetaryl bromides and phenylboronic acids came off in excellent yields in DMF–H2O in the presence of K2CO3 as a base with low catalyst loadings (0.1%) at room temperature.

Chiral Polyureas Derived Cinchona Alkaloids: Highly Efficient Bifunctional Organocatalysts for the Asymmetric Michael Addition Reaction

AbstractRepetitive Mizoroki‐Heck (MH) coupling polymerization was used to create novel chiral polyureas with cinchona alkaloids in the main chain. Apart from two‐component polycondensation of cinchona urea dimers with diiodobenzene via MH reaction conditions, some chiral polyureas were easily polymerized under self polycondensation to yield the chiral polymers. The asymmetric Michael addition reaction was successfully carried out using chiral polymers derived cinchona urea. Interestingly, phenolic‐based chiral polymers served as heterogeneous catalysts for the enantioselective Michael reaction, with high catalytic activity and excellent enantioselectivities (up to 99 % ee). These polymeric catalysts were also stable, and they could be recycled and reused.

Palladium-Catalyzed γ,γ'-Diarylation of Free Alkenyl Amines.

The direct difunctionalization of alkenes is an effective way to construct multiple C-C bonds in one-pot using a single functional group. The regioselective dicarbofunctionalization of alkenes is therefore an important area of research to rapidly obtain complex organic molecules. Herein, we report a palladium-catalyzed γ,γ'-diarylation of free alkenyl amines through interrupted chain walking for the synthesis of Z-selective alkenyl amines. Notably, while 1,3-dicarbofunctionalization of allyl groups is well precedented, the present disclosure allows 1,3-dicarbofunctionalization of highly substituted allylamines to give highly Z-selective trisubsubstituted olefin products. This cascade reaction operates via an unprotected amine-directed Mizoroki-Heck (MH) pathway featuring a β-hydride elimination to selectively chain walk to furnish a new terminal olefin which then generates the cis-selective alkenyl amines around the sterically crowded allyl moiety. This operationally simple protocol is applicable to a variety of cyclic, branched, and linear secondary and tertiary alkenylamines, and has a broad substrate scope with regard to the arene coupling partner as well. Mechanistic studies have been performed to help elucidate the mechanism, including the presence of a likely unproductive side C-H activation pathway.

Pd(II)/Pd(0) Anchored on Magnetic Organic–Inorganic Hybrid Mesoporous Silica Nanoparticles: A Nanocatalyst for Suzuki–Miyaura and Heck–Mizoroki Coupling Reactions

Pd(II)/Pd(0) Anchored on Magnetic Organic–Inorganic Hybrid Mesoporous Silica Nanoparticles: A Nanocatalyst for Suzuki–Miyaura and Heck–Mizoroki Coupling Reactions

Water-Sculpting of a Heterogeneous Nanoparticle Precatalyst for Mizoroki-Heck Couplings under Aqueous Micellar Catalysis Conditions.

Powdery, spherical nanoparticles (NPs) containing ppm levels of palladium ligated by t-Bu3P, derived from FeCl3, upon simple exposure to water undergo a remarkable alteration in their morphology leading to nanorods that catalyze Mizoroki-Heck (MH) couplings. Such NP alteration is general, shown to occur with three unrelated phosphine ligand-containing NPs. Each catalyst has been studied using X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and cryogenic transmission electron microscopy (cryo-TEM) analyses. Couplings that rely specifically on NPs containing t-Bu3P-ligated Pd occur under aqueous micellar catalysis conditions between room temperature and 45 °C, and show broad substrate scope. Other key features associated with this new technology include low residual Pd in the product, recycling of the aqueous reaction medium, and an associated low E Factor. Synthesis of the precursor to galipinine, a member of the Hancock family of alkaloids, is suggestive of potential industrial applications.

Biomass waste rice husk derived silica supported palladium nanoparticles: an efficient catalyst for Suzuki–Miyaura and Heck–Mizoroki cross-coupling reactions

Here, we report an inexpensive, versatile, and environmentally benign biomass waste rice husk derived amorphous silica-supported palladium (PdNPs/RH-SiO2) nano-catalyst for Suzuki–Miyaura and Heck–Mizoroki cross-coupling reactions. The proposed catalyst was prepared in two steps. In the first step, amorphous SiO2 obtained by calcination of rice husk and the following deposition of palladium nanoparticles by using the chemical reduction method in the second step. The physico-chemical properties of the catalysts were investigated by N2 adsorption–desorption, XRD, XPS, 29Si CP-MAS NMR, and TEM analysis. The palladium content in the catalysts has been determined by ICP-OES analysis. The 1% PdNPs/RH-SiO2 exhibited excellent catalytic performance for Suzuki–Miyaura and Heck–Mizoroki C–C cross-coupling reactions to produce biaryl and stilbene compounds with >99% selectivity and excellent TON values (529 and 524). Furthermore, the catalyst is repeatedly used for four consecutive cycles without a significant drop in the yield.

Steps Forward toward the Substitution of Conventional Solvents in the Heck–Mizoroki Coupling Reaction: Glycerol-Derived Ethers and Deep Eutectic Solvents as Reaction Media

Glycerol-derived ethers and their eutectic mixtures with two renewable ammonium salts (ChCl and N00Cl) are effectively used as new green solvents for the immobilization of PVP-Palladium nanoparticles. Those air-stable, selective, and recoverable catalytic systems are applied in the benchmark Heck–Mizoroki coupling reaction between iodobenzene and n-butyl acrylate in order to evaluate the influence of the different solvation properties of the solvent on the reaction results. The HBD ability (α acidity) of the solvent seems to play a crucial role in the reaction selectivity.

Synthesis of glucoside-based imidazolium salts for Pd-catalyzed cross-coupling reaction in water

Sugar-based imidazolium salts (IMSs) represent an outstanding type of material making them eye-catching for a wide variety of applications. Herein, a series of glucoside-based IMSs (Glu-IMSs) combining glucoside and imidazolium head groups with different substituents were synthesized. The catalytic activities of these Glu-IMSs were evaluated by Pd-catalyzed Heck–Mizoroki and Suzuki–Miyaura reactions in water. Among them, the Glu-IMSs contain both –OH and NHCs coordination sites was found to be the most efficient ancillary ligand in comparison with other Glu-IMSs with just single NHCs coordination site. The HR-TEM analysis showed that the palladium nanoparticles stabilized by the Glu-IMSs with an average size of ~4.0 nm was formed in the reaction system, which may be act as an efficient real catalytic species. Under the optimized reaction conditions, a series of novel fluorine-cored organic small molecule functional materials were synthesized with favorable yields.

Synthesis of Cinchona Urea Polymers and Their Evaluation as Catalyst in the Asymmetric Reactions

AbstractChiral polyureas of cinchona alkaloids were synthesized via repetitive Mizoroki‐Heck (MH) coupling reaction. The Pd‐catalyzed polycondensation of cinchona urea dimers 6 and aromatic diiodide 7 afforded the chiral polyureas (P1−P4). The catalytic activity of the chiral polymers was subsequently investigated. The asymmetric Michael addition of ketoesters to nitroolefins was successfully catalyzed by the polymeric organocatalysts (P1−P4) to give the corresponding Michael adducts with high catalytic activities and excellent enantionselectivities (up to >99% ee). The polymeric catalysts were insoluble in commonly used organic solvents. They were easily recovered and reused several times without any loss of the catalytic activity.

Design and synthesis of cinchona-based chiral hyperbranched polymers and their application in asymmetric reactions

Cinchona-based chiral hyperbranched polymers (HBPs) were designed and successfully synthesized via the Mizoroki-Heck (MH) coupling reaction. AB2 and A2B-type chiral monomers were prepared from cinchona squaramide derivatives, where A (vinyl) reacted only with B (iodophenyl) under MH reaction conditions. The chiral HBPs obtained by the MH polymerization contained cinchona squaramide moieties and demonstrated excellent diastereoselectivity and enantioselectivity in asymmetric Michael addition reactions of methyl 2-oxocyclopentanecarboxylate and trans-β-nitrostyrene. These newly designed HBPs were structurally robust and could be reused for further reaction without losing their catalytic activity.

Pd–ninhydrin immobilized on magnetic nanoparticles: synthesis, characterization, and application as a highly efficient and recoverable catalyst for Suzuki–Miyaura and Heck–Mizoroki C–C coupling reactions

In this work by controlling the interaction between the inorganic complexes and the support material, we have designed a high-activity nanostructured combined of magnetic nanoparticles and Pd–ninhydrin-terminated complex as catalyst. The as-prepared catalyst was characterized by FT-IR, XRD, VSM, SEM, EDAX, ICP, and TGA techniques. This magnetic nanostructure can be used as a novel, green, and efficient heterogeneous catalyst for Suzuki–Miyaura and Heck–Mizoroki C–C coupling reactions. This catalyst showed promising catalytic activity and excellent yields toward various aryliodides and arylbromides in mild reaction conditions. In Suzuki–Miyaura reactions, various aryl halides (I, Br) were coupled with phenyl boronic acids in 5 mg of catalyst and 8 mg of catalyst used for Mizoroki–Heck reaction of aryl halides (I, Br) with n-butyl acrylate or acrylonitrile. The catalyst was reusable and recycled six times without a significant loss in activity and leaching of palladium.

Mizoroki–Heck Cross‐Coupling of Acrylate Derivatives with Aryl Halides Catalyzed by Palladate Pre‐Catalysts

The Mizoroki–Heck (MH) reaction involving aryl halides with various acrylates and acrylamides has been studied using air and moisture‐stable imidazolium‐based palladate pre‐catalysts. These pre‐catalysts can be converted into Pd‐NHC species (NHC = N‐heterocyclic carbene) under catalytic conditions and are capable of facilitating the Mizoroki–Heck reaction of aryl halides with various acrylates. The effects of solvent, catalyst loading, temperature and bases on the reaction outcome have been investigated. Various coupling partners were tolerated under the optimal reaction conditions catalyzed by palladate 1, [SIPr·H][Pd(η3‐2‐Me‐allyl)Cl2]. The efficiency of the optimized synthetic methodology was tested on various aryl halides and substituted acrylates as well as acrylamides. The MH reaction yielded the coupled products in good to excellent isolated yields (up to 98%).

Biochar as heterogeneous support for immobilization of Pd as efficient and reusable biocatalyst in C–C coupling reactions

Biochar is a stable and carbon‐rich solid which has a high density of carbonyl, hydroxyl and carboxylic acid functional groups on its surface. In this work, the surface of biochar nanoparticles (BNPs) was modified with 3‐choloropropyltrimtoxysilane and further 2‐(thiophen‐2‐yl)‐1H‐benzo[d]imidazole was anchored on its surface. Then, palladium nanoparticles were fabricated on the surface of the modified BNPs and further the catalytic application was studied as recyclable biocatalyst in carbon–carbon coupling reactions such as Suzuki–Miyaura and Heck–Mizoroki cross‐coupling reactions. The structure of the catalyst was characterized using scanning electron microscopy, transmission electron microscopy, energy‐dispersive X‐ray spectroscopy, thermogravimetric analysis, X‐ray diffraction and atomic absorption spectroscopy. The catalyst can be reused several times without a decrease in its catalytic efficiency. In addition to the several advantages reported, application of biochar as catalyst support for the first time is a major novelty of the present work.

Design and synthesis of chiral hyperbranched polymers containing cinchona squaramide moieties and their catalytic activity in the asymmetric Michael addition reaction

Chiral hyperbranched polymers (HBP) containing cinchona alkaloids were synthesized using a Mizoroki–Heck (MH) coupling polymerization reaction between a cinchona squaramide dimer and tri- or tetra-substituted aromatic iodides. This is a new type of polymeric chiral organocatalyst. We found that the as-obtained chiral HBPs show excellent catalytic activity in the asymmetric Michael reaction. Almost perfect enantioselectivity (>99% ee) was achieved in the reaction of β-ketoester and trans-β-nitrostyrene. The three-dimensional network structure of the chiral HBPs is structurally robust and can be reused for further reaction without any loss in their catalytic activity.

Palladium nanoparticles immobilized on EDTA-modified Fe3O4@SiO2: a highly stable and efficient magnetically recoverable catalyst for the Heck–Mizoroki coupling reactions

Palladium nanoparticles supported on EDTA-modified Fe3O4@SiO2 NPs as an efficient and magnetically reusable nanocatalyst was applied for the Heck cross-coupling reactions. The catalyst was very effective for the Heck reaction of aryl halides (iodides, bromides, and chlorides) with alkenes and conversion was excellent in most cases with higher TOF (turn over frequency). Moreover, the catalyst could be recycled for eight runs without any significant loss of catalytic activity, showing its superiority over homogeneous catalysts for industrial and chemical applications. Also, the leaching of the catalyst has been examined by a hot filtration test and ICP analysis.

New C-scorpionate nickel(II) catalyst for Heck C–C coupling under unconventional conditions

The new C-scorpionate Ni(II) complex [NiCl{κ3-HC(pz)3}]Cl (pz = pyrazol-1-yl) is the first nickel homoscorpionate tris(pyrazol-1-yl)methane type complex to be applied as catalyst for the Heck–Mizoroki C–C cross coupling. The microwave-assisted reaction of butyl acrylate and 4-halogeno-anisole was efficiently catalyzed by the above Ni(II) complex, in ionic liquid medium, yielding the C–C coupling product in good yields. The stability of [NiCl{κ3-HC(pz)3}]Cl in the ionic liquid allowed its recycling and re-use for several consecutive catalytic cycles with preserved activity.