- Mechanistic and kinetic studies of cobalt macrocycles in a photochemical CO2 reduction system: Evidence of Co-CO2 adducts as intermediates
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Cobalt macrocycles mediate electron transfer in the photoreduction of CO2 with p-terphenyl as a photosensitizer and a tertiary amine as a sacrificial electron donor in a 5:1 acetonitrile/methanol mixture. The mechanism and kinetics of this system have been studied by continuous and flash photolysis techniques. Transient spectra provide evidence for the sequential formation of the p-terphenyl radical anion, the CoIL+ complex, the [CoIL-CO2]+ complex, and the [S-CoIIIL-(CO22-)]+ complex (L = HMD = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene; S = solvent) in the catalytic system. The electron-transfer rate constant for the reaction of p-terphenyl radical anion with CoIIL2+ is 1.1 × 1010 M-1 s-1 and probably diffusion controlled because of the large driving force (～+1.1 V). Flash photolysis studies yield a rate constant 1.7 × 108 M-1 s-1 and an equilibrium constant 1.1 × 104 M-1 for the binding of CO2 to CoIL+ in the catalytic system. These are consistent with those previously obtained by conventional methods in acetonitrile. Studies of catalytic systems with varying cobalt macrocycles highlight some of the factors controlling the kinetics of the photoreduction of CO2. Steric hindrance and reduction potentials are important factors in the catalytic activity for photochemical CO2 reduction.
- Ogata, Tomoyuki,Yanagida, Shozo,Brunschwig, Bruce S.,Fujita, Etsuko
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Read Online
- Cyclodextrins or calixarenes: What is the best mass transfer promoter for Suzuki cross-coupling reactions in water?
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Cyclodextrins or calixarenes possessing extended hydrophobic host cavities and surface-active properties were found to be very efficient as mass transfer promoters for the palladium-mediated Suzuki cross-coupling reaction of 1-iodo-4-phenyl-benzene and ph
- Hapiot,Lyskawa,Bricout,Tilloy,Monflier
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Read Online
- The synthesis of SBA-Pr-3AP@Pd and its application as a highly dynamic, eco-friendly heterogeneous catalyst for Suzuki–Miyaura cross-coupling reaction
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The hexagonal mesoporous organic–inorganic hybrid as a new nanocatalyst was prepared by the treatment of SBA-15 with (3-chloropropyl)triethoxysilane, the 2,4,6-triamino pyrimidine ligand, and then PdCl2 to obtain the SBA-15-propyl-triamino pyrimidine@Pd called as SBA-Pr-3AP@Pd, which was examined through Suzuki–Miyaura cross-coupling reaction by several aryl halides and phenylboronic acid under mild conditions in high yield.
- Mohajer, Fatemeh,Mohammadi Ziarani, Ghodsi,Badiei, Alireza
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Read Online
- PdCl2(SEt2)2 and Pd(OAc)2: Simple and efficient catalyst precursors for the Suzuki cross-coupling reaction
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PdCl2(SEt2)2 and Pd(OAc)2 efficiently promote the cross-coupling of aryl bromides and chlorides with arylboronic acids under mild reaction conditions. These methods tolerate a variety of functional groups and represent, from a synthetic point of view, two of the simplest catalyst precursors that mediate the Suzuki cross-coupling reaction at room temperature. (C) 2000 Elsevier Science Ltd.
- Zim,Monteiro,Dupont
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Read Online
- Postsynthetic Metalation of a Robust Hydrogen-Bonded Organic Framework for Heterogeneous Catalysis
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Hydrogen-bonded organic framework (HOF)-based catalysts still remain unreported thus far due to their relatively weak stability. In the present work, a robust porous HOF (HOF-19) with a Brunauer-Emmett-Teller surface area of 685 m2 g-1 was reticulated from a cagelike building block, amino-substituted bis(tetraoxacalix[2]arene[2]triazine), depending on the hydrogen bonding with the help of π-πinteractions. The postsynthetic metalation of HOF-19 with palladium acetate afforded a palladium(II)-containing heterogeneous catalyst with porous hydrogen-bonded structure retained, which exhibits excellent catalytic performance for the Suzuki-Miyaura coupling reaction with the high isolation yields (96-98%), prominent stability, and good selectivity. More importantly, by simple recrystallization, the catalytic activity of deactivated species can be recovered from the isolation yield 46% to 92% for 4-bromobenzonitrile conversion at the same conditions, revealing the great application potentials of HOF-based catalysts.
- Han, Bin,Wang, Hailong,Wang, Chiming,Wu, Hui,Zhou, Wei,Chen, Banglin,Jiang, Jianzhuang
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Read Online
- Synthesis and characterization of palladium nanoparticles immobilized on graphene oxide functionalized with triethylenetetramine or 2,6-diaminopyridine and application for the Suzuki cross-coupling reaction
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Graphene oxide (GO) was functionalized with two organic ligands, triethylenetetramine (TETA) or 2,6-diaminopyridine (DAP), followed by palladium nanoparticles (Pd NPs) for the synthesis of Pd NPs/GO-TETA and Pd NPs/GO-DAP nanocomposites, respectively. The two heterogeneous nanocomposites were fully characterized and their efficiency was investigated for C[sbnd]C bond formation for the synthesis of biaryl compounds via the Suzuki cross-coupling reaction of aryl halides with arylboronic acid derivatives. The obtained results indicated that the Pd NPs/GO-TETA nanocomposite was more effective in the Suzuki coupling reaction as compared to Pd NPs/GO-DAP. Thus, the Suzuki cross-coupling reaction of different aryl halides with arylboronic acid derivatives using Pd NPs/GO-TETA nanocomposite catalyst in the presence of Na2CO3 as base in DMF/H2O (1/1) as solvent at 90 °C was carried out to afford the desired biaryl compounds in high to excellent yields (81–100%) and short reaction times (10–90 min). Additionally, Pd NPs/GO-TETA nanocomposite can be recovered and reused for 8 consecutive runs without any apparent loss of its catalytic activity, proving its high stability and potential use in organic transformations.
- Boukherroub, Rabah,Mirza-Aghayan, Maryam,Mohammadi, Marzieh
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- Silk?Fibroin-Supported Palladium Catalyst for Suzuki-Miyaura and Ullmann Coupling Reactions of Aryl Chlorides
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Recently, we have reported the preparation of a silk fibroin-supported Palladium catalyst (Pd/SF) and its use in the Suzuki-Miyaura cross-coupling of aryl iodides. Since its synthetic applicability and structural features are still far from being fully ex
- Albano, Gianluigi,Farinola, Gianluca M.,Giannini, Cinzia,Musio, Roberta,Omenetto, Fiorenzo G.,Rizzo, Giorgio,Sibillano, Teresa
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- Solvent coordination to palladium can invert the selectivity of oxidative addition
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Reaction solvent was previously shown to influence the selectivity of Pd/PtBu3-catalyzed Suzuki-Miyaura cross-couplings of chloroaryl triflates. The role of solvents has been hypothesized to relate to their polarity, whereby polar solvents stabilize anionic transition states involving [Pd(PtBu3)(X)]- (X = anionic ligand) and nonpolar solvents do not. However, here we report detailed studies that reveal a more complicated mechanistic picture. In particular, these results suggest that the selectivity change observed in certain solvents is primarily due to solvent coordination to palladium. Polar coordinating and polar noncoordinating solvents lead to dramatically different selectivity. In coordinating solvents, preferential reaction at triflate is likely catalyzed by Pd(PtBu3)(solv), whereas noncoordinating solvents lead to reaction at chloride through monoligated Pd(PtBu3). The role of solvent coordination is supported by stoichiometric oxidative addition experiments, density functional theory (DFT) calculations, and catalytic cross-coupling studies. Additional results suggest that anionic [Pd(PtBu3)(X)]- is also relevant to triflate selectivity in certain scenarios, particularly when halide anions are available in high concentrations.
- Elias, Emily K.,Neufeldt, Sharon R.,Rehbein, Steven M.
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p. 1618 - 1628
(2022/02/21)
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- Suzuki cross-coupling of hexachlorobenzene promoted by the Buchwald ligands
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The study of cross-coupling between hexachlorobenzene and phenylboronic acid comprised five Buchwald ligands, from which 2-dicyclohexylphosphino-2′-(dimethylamino)biphenyl (DavePHOS) provided the best conversion. When excess of phenylboronic acid was used, a mixture of isomeric tri-, tetra- and pentaphenyl-substituted derivatives in the ～10:70:20 ratio was obtained, along with minor amounts of hydrodechlorination products.
- Burukin, A. S.,Vasil’ev, A. A.,Zhdankina, G. M.,Zlotin, S. G.
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p. 169 - 172
(2022/02/17)
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- Nickel-Catalyzed Direct Cross-Coupling of Aryl Sulfonium Salt with Aryl Bromide
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The direct cross-couplings of aryl sulfonium salts with aryl halides could be achieved by using nickel as a reaction catalyst. The reactions proceeded efficiently via C-S bond activation in the presence of magnesium turnings and lithium chloride in THF at ambient temperature to afford the corresponding biaryls in moderate to good yields, potentially serving as an attractive alternative to conventional cross-coupling reactions employing preprepared organometallic reagents.
- Ma, Na-Na,Ren, Jing-Ao,Liu, Xiang,Chu, Xue-Qiang,Rao, Weidong,Shen, Zhi-Liang
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supporting information
p. 1953 - 1957
(2022/03/27)
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- Preparation and characterization of cellulose sulfate/Pd nanocatalsysts with remarkable efficiency for Suzuki–Miyaura reaction
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Heterogeneous catalysis with noble metal NPs are quite attractive due to unique surface chemistry and tuneable physicochemical properties. In this work, an efficient and simple method was used to synthesize palladium nanoparticles supported on cellulose sulfate. The resulted composites were characterized using various techniques such as X-ray powder diffraction (XRD), FT-IR, energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA) to verify the chemical structure and morphological properties of nanocatalysts. Next, the synthesized catalyst was utilized in Suzuki–Miyaura reaction between aryl bronic acid and different aryl halides. The catalysis reaction was carried out under atmospheric pressure where high efficiency, unique and simple work-up procedure as well as excellent yields were achieved.
- Jokar, Mitra,Naeimi, Hossein,Nabi Bidhendi, Gholamreza
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- Agro-Waste Generated Pd/CAP-Ash Catalyzed Ligand-Free Approach for Suzuki–Miyaura Coupling Reaction
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Abstract: We converted agro-waste Custard Apple Peels (CAP) to ash via thermal treatment, on which Pd(OAc)2 was immobilized easily that produced a low-cost, highly efficient Pd/CAP-ash catalyst. The prepared catalyst was fully characterized by using FT-IR, SEM, EDX, XRF, DSC-TGA, BET, HR-TEM, and XPS techniques. The Pd/CAP-ash catalyst was conveniently applied for the Suzuki–Miyaura coupling reaction under external base free and ligand-free conditions in an aqueous-organic solvent to produce biphenyls in good to excellent yields. The main attraction of our protocol an application of palladium-supported agro-waste material which is easily recoverable and recyclable provides mono and bis-coupled derivatives in a short reaction time. Graphic Abstract: [Figure not available: see fulltext.].
- Patil, Rupesh C.,Jagdale, Ashutosh A.,Patil, Uttam P.,Ghodake, Jeevan S.,Mali, Sawanta S.,Hong, Chang K.,Patil, Suresh S.
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supporting information
p. 3617 - 3631
(2021/04/02)
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- Triptycene ring metal palladium compound and application thereof
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The invention discloses a triptycene cyclometalated palladium compound and an application thereof. The triptycene cyclometalated palladium compound has the following general formula, wherein three RAscan be the same or different and are respectively and independently expressed as R1-(Z1-A1-Z2)x-,wherein the three RBs can be the same or different and are respectively and independently expressed asR2-(Z3-A2-Z4)y-, the two RCs may be the same or different, each independently expressed as R3-(Z5-A3-Z6)z-. The triptycene cyclometalated palladium compound provided by the invention has a triptycenelarge-steric-hindrance group, and can stabilize a zero-valent palladium intermediate in a catalytic cycle, so that the catalytic efficiency is improved, the use amount of a catalyst can be reduced tobe less than ten thousandth, and the compound is simple in synthesis step, high in yield, relatively low in cost and suitable for various substrates, and the method has an important application valuefor researching the progress and application of the coupling reaction.
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Paragraph 0085-0092
(2021/02/24)
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- 3,3'-((Arylmethylene)bis(4-methoxy-3,1-phenylene)) dipyridine derivatives as convenient ligands for Suzuki–Miyaura chemo- and homoselective cross-coupling reactions
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Four novel N,N-bidentate triarylmethane-based ligands bearing β-pyridyl residues have been prepared and the catalytic activity of their in-situ generated palladium complexes were studied in the Suzuki–Miyaura cross-coupling reactions. Air and moisture stable 3,3'-((arylmethylene)bis(4-methoxy-3,1-phenylene))dipyridines L1-3 showed excellent activity in the Suzuki coupling reactions of aryl halides with aryl boronic acids under thermal and sonochemical reaction conditions. The described methodology provided good to high yields in short reaction times at ambient conditions. Moreover, it offered a straightforward way for Suzuki–Miyaura chemo- and homoselective cross-coupling of aryl halides with phenyl boronic acid. The structures of synthesized compounds were fully characterized by FT-IR, 1H-NMR, 13C-NMR, and elemental analyses. The coordination of palladium acetate to nitrogen sites of L1 was also studied using FTIR spectroscopy, EDX analysis and SEM observations. Graphic abstract: The in-situ generated Pd-complexes of N,N-bidentate ligands L1-3 are described as robust and highly effective catalytic systems for the Suzuki cross-coupling of aryl halides with aryl boronic acids under thermal and sonochemical reaction conditions.[Figure not available: see fulltext.]
- Hosseini, Raziyeh,Mohammadiannejad, Kazem,Ranjbar-Karimi, Reza
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- A Bis (BICAAC) Palladium(II) Complex: Synthesis and Implementation as Catalyst in Heck-Mizoroki and Suzuki-Miyaura Cross Coupling Reactions
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Carbenes are one of the most appealing, well-explored, and exciting ligands in modern chemistry due to their tunable stereoelectronic properties and a wide area of applications. A palladium complex (BICAAC)2PdCl2 with a recently discovered cyclic (alkyl)(amino)carbene having bicyclo[2.2.2] octane skeleton (BICAAC) was synthesized and characterized. The enhanced σ-donating and π-accepting ability of this carbene lend a hand to form a robust Pd-carbene bond, which allowed us to probe its reactivity as a precatalyst in Heck-Mizoroki and Suzuki-Miyaura cross-coupling reactions with low catalyst loading in open-air conditions. The diverse range of substrates was explored for both the cross-coupling reactions. To get a better understanding of the catalytic reactions, several analytical techniques such as field-emission scanning electron microscopy, high-resolution transmission electron microscopy, and powder X-ray diffraction were employed in a conclusive manner.
- Chakrabortty, Soumyadeep,Kaur, Mandeep,Adhikari, Manu,Manar, Krishna K.,Singh, Sanjay
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supporting information
p. 6209 - 6217
(2021/05/06)
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- Charge Neutral [Cu2L2] and [Pd2L2] Metallocycles: Self-Assembly, Aggregation, and Catalysis
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A range of morphologically distinct metallosupramolecular Cu(II) and Pd(II) complexes has been constructed, based on the tritopic ligand 1,1′,1″-(benzene-1,3,5-triyl)tris(4,4-dimethylpentane-1,3-dione) (H3L). By control of the reaction conditions, it is possible to generate distinct coordination assemblies possessing either macrocyclic or polymeric structures and more importantly distinct activity in catalysis of the Suzuki-Miyaura cross-coupling.
- Ko?odziejski, Micha?,Brock, Aidan J.,Kurpik, Gracjan,Walczak, Anna,Li, Feng,Clegg, Jack K.,Stefankiewicz, Artur R.
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p. 9673 - 9679
(2021/06/30)
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- Buchwald ligand-assisted Suzuki cross-coupling of polychlorobenzenes
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Screening of four Buchwald ligands for the cross-coupling of isomeric di-, tri- and tetrachlorobenzenes with arylboronic acids revealed that good yields of exhaustive substitution can be best provided by 2-dicyclohexylphosphino-2′-(dimethylamino) biphenyl (DavePHOS).
- Burukin, Alexander S.,Vasil'ev, Andrei A.,Zhdankina, Galina M.,Zlotin, Sergei G.
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p. 400 - 402
(2021/06/07)
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- Highly Active Fe3O4@SBA-15@NHC-Pd Catalyst for Suzuki–Miyaura Cross-Coupling Reaction
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A novel Pd-NHC functionalized magnetic Fe3O4@SBA-15@NHC-Pd was synthesized and used as an efficient heterogeneous catalyst in the Suzuki–Miyaura C–C bond formation reactions. The Fe3O4@SBA-15@NHC-Pd characterized by X-Ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy?(TEM), Energy Dispersive X-ray analysis (EDX), Thermogravimetric Analysis (TGA), Differential Thermal Analysis (DTA). The Inductively Coupled Plasma-Optical emission spectroscopy (ICP-OES)?analysis was used to determine the exact amount of Pd (0.33?wt%) in Fe3O4@SBA-15@NHC-Pd. The TEM images of the catalyst showed the existence of palladium nanoparticles immobilized in the catalyst's structure, while no reducing agent was used. The NHC moieties in the catalyst structure could be stabilize Pd(0) nanoparticles prevents agglomeration. The magnetic catalyst was effectively used in the Suzuki–Miyaura cross-coupling reaction of substituted phenylboronic acid derivatives with (hetero)aryl bromides in the presence of a K2CO3 at room temperature in aqueous media and magnetic catalyst could be simply extracted from the reaction mixture by an external magnet. Different aryl bromides were converted to coupled-products in excellent yields with spectacular TOFs values (up to 1,960,339?h?1); in the presence of 1?mg of Fe3O4@SBA-15@NHC-Pd catalyst (contains 3.1 × 10–6?mol% Pd) at room temperature in aqueous media. After reusability experiments, it is found that this catalyst was effectively used up to ten times in the reaction with almost consistent catalytic efficiency. A decrease in the activity of the 10th reused catalyst was found as 9%. Graphic Abstract: [Figure not available: see fulltext.]
- ?zdemir, ?smail,Akko?, Mitat,Alt?n, Serdar,Bu?day, Nesrin,Ya?ar, Sedat
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- Magnetite@MCM-41 nanoparticles as support material for Pd-N-heterocyclic carbene complex: A magnetically separable catalyst for Suzuki–Miyaura reaction
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The Magnetite@MCM-41@NHC@Pd catalyst was obtained with Pd metal bound to the NHC ligand anchored to the surface of Fe3O4@MCM-41. It was characterized by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy disperse X-ray analysis (EDX), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and scanning electron microscopy (SEM). The amount of Pd in the Magnetite@MCM-41@NHC@Pd was measure by inductively coupled plasma–optical emission spectroscopy (ICP-OES) analysis. The catalytic activity of Magnetite@MCM-41@NHC@Pd heterogeneous catalyst done on Suzuki–Miyaura reactions of aryl halides with different substituted arylboronic acid derivatives. All coupling reactions afforded excellent yields and up to 408404 Turnover Frequency (TOF) h?1 in the presence of 2 mg of Magnetite@MCM-41@NHC@Pd catalyst (0.0564 mmol g?1, 0.01127 mmol% Pd) at room temperature in 2-propanol/H2O (1:2). Moreover, Magnetite@MCM-41@NHC@Pd catalyst was recover by applying the magnet and reused for another reaction. The catalyst showed excellent structural and chemical stability and reused ten times without a substantial loss in its catalytic performance.
- Akko?, Mitat,Bu?day, Nesrin,Alt?n, Serdar,Ya?ar, Sedat
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- Synthesis of tetranuclear complex of Pd(II) with thiosemicarbazone ligands derived from 2-quinolone and its catalytic evaluation in Suzuki–Miyaura-type coupling reactions and alkoxylation of chloroquinolines
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A tetranuclear palladium(II) complex [(Pd(H-6MOQtsc-Ph))4] was obtained from the reaction between 6-methyl-2-oxo-1,2-dihydroquinoline-3-carboxaldehyde-4(N)-phenylthiosemicarbazone [H2-6MOQtsc-Ph] and K2[PdCl4]. The ligand and the Pd(II) complex were characterized by Fourier transform infrared spectroscopy (FT-IR), UV–visible and 1H NMR spectroscopy. X-ray diffraction studies confirmed the tetrameric nature of the complex with the coordination of ligand through quinolone carbonyl, azomethine nitrogen and thiolate sulfur atoms, and the fourth site is occupied by 2-quinolone nitrogen atom of the adjacent ligand. The synthesized complex was tested as catalyst in Suzuki–Miyaura coupling reaction between various chloroquinoline derivatives with phenylboronic acid. The reactions afforded unexpected C-alkoxylated (C-O coupling) products instead of more expected C-arylated (C-C coupling) products in the respective alcoholic mediums. However, the reactions with traditional aryl halides probed with very good yield of the corresponding C-C coupling products.
- Nandhini, Sundar,Dharani, Sivadasan,Elamathi, Chennakrishnan,Dallemer, Frederic,Prabhakaran, Rathinasabapathi
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- Sterically enhanced 2-iminopyridylpalladium chlorides as recyclable ppm-palladium catalyst for Suzuki–Miyaura coupling in aqueous solution
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Sterically hindered 2-iminopyridine derivatives and their palladium chlorides complexes are designed and prepared, which efficiently promote the Suzuki–Miyaura coupling (SMC) reaction in aqueous solution. Besides the good to excellent yields and broad substrate scope, these catalysts can be reused for at least four new batches of the substrates. Spontaneous separation of coupling products in the aqueous reaction medium is the additional striking feature of this catalytic process. Furthermore, catalytic performance of palladium complexes bearing the azo-bridged phenyl groups was greatly influenced by the UV irradiation due to the cis/trans photoisomerization of azo unit of the catalysts. In conclusion, titled palladium complexes provide a green, sustainable, cost-effective, and convenient process to synthesize SMC products at multi-gram-scale reaction.
- Liang, Tongling,Lin, Wenhua,Ma, Yanping,Sun, Wen-Hua,Zhang, Liping
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- New Nickel-Based Catalytic System with Pincer Pyrrole-Functionalized N-Heterocyclic Carbene as Ligand for Suzuki-Miyaura Cross-Coupling Reactions
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A new catalytic system with Ni(NO3)2·6H2O as the catalyst and a pincer pyrrole-functionalized N-heterocyclic carbene as the ligand was employed in the Suzuki-Miyaura cross-coupling reactions of aryl iodides with arylboronic acids. With 5 mol% catalyst, the catalytic reactions proceeded at 160 °C, giving coupling products in isolated yields of up to 94% in short reaction times (1-4 h). The system worked efficiently with aryl iodides bearing electron-donating or electron-withdrawing groups and arylboronic acids with electron-donating groups. Steric effects were observed for both aryl iodides and arylboronic acids. It is proposed that the reactions underwent a Ni(I)/Ni(III) catalytic cycle.
- Guo, Zhifo,Lei, Xiangyang
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supporting information
(2021/09/11)
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- Photoelectric properties of aromatic triangular tri-palladium complexes and their catalytic applications in the Suzuki-Miyaura coupling reaction
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The photoelectric properties and catalytic activities of substituted triphenylphosphine and sulfur/selenium ligand supported aromatic triangular tri-palladium complexes1-4, abbreviated as [Pd3]+, were investigated. The cyclic voltammogram of [Pd3]+in CH3CN-nBu4NPF6showed a single quasi-reversible wave which was consistent with their robust property and provided preliminary proof for their electron transfer processes in catalysis. With excitation at 267 nm, [Pd3]+exhibited strong ratiometric fluorescence at 550 and 780 nm at a temperature gradient from 77 K to 287 K. These peculiar triangular tri-palladium complexes showed excellent catalytic activities and exclusive reactivity with aryl iodides over the other halogenated aromatics in the Suzuki-Miyaura coupling reaction. The electronic and steric hindrance effects of substituents on the aryl iodides and aryl boronic acids including heteroaromatics like pyridine, pyrazine and thiophenes were explored and most substrates achieved up to 99% of yields. (2-[1,1′-Biphenyl]-2-ylbenzothiazole) which was analogous to the selective cyclooxygenase-2 (COX-2) inhibitors was also synthesized with our tri-palladium catalyst and gave good isolated yield (94%). The study of the catalytic process revealed that the mechanism of the reaction may involve the replacement of the sulphur ligand on [Pd3]+by iodine from aryl iodides, which was beneficial for the matching of C-I bond energy.
- Li, Jia,Li, Xujun,Liu, Xiang,Maestri, Giovanni,Malacria, Max,Wang, Xiaoshuang,Wang, Yanlan,Wu, Lingang
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supporting information
p. 11834 - 11842
(2021/09/06)
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- 1,2,3-Triazole framework: a strategic structure for C-H?X hydrogen bonding and practical design of an effective Pd-catalyst for carbonylation and carbon-carbon bond formation
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1,2,3-Triazole is an interesting N-heterocyclic framework which can act as both a hydrogen bond donor and metal chelator. In the present study, C-H hydrogen bonding of the 1,2,3-triazole ring was surveyed theoretically and the results showed a good agreement with the experimental observations. The click-modified magnetic nanocatalyst Pd@click-Fe3O4/chitosan was successfully prepared, in which the triazole moiety plays a dual role as both a strong linker and an excellent ligand and immobilizes the palladium species in the catalyst matrix. This nanostructure was well characterized and found to be an efficient catalyst for the CO gas-free formylation of aryl halides using formic acid (HCOOH) as the most convenient, inexpensive and environmentally friendly CO source. Here, the aryl halides are selectively converted to the corresponding aromatic aldehydes under mild reaction conditions and low Pd loading. The activity of this catalyst was also excellent in the Suzuki cross-coupling reaction of various aryl halides with phenylboronic acids in EtOH/H2O (1?:?1) at room temperature. In addition, this catalyst was stable in the reaction media and could be magnetically separated and recovered several times.
- Hajipour, Abdol Reza,Hosseini, Seyed Mostafa,Jahromi, Maryam Dehdashti,Mohammadsaleh, Fatemeh,Niknam, Khodabakhsh
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p. 20812 - 20823
(2021/07/01)
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- A magnetic palladium nickel carbon nanocomposite as a heterogeneous catalyst for the synthesis of distyrylbenzene and biphenyl derivatives
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A magnetic palladium nickel carbon (Fe3O4@Pd@Ni/C) nanocomposite has been synthesized using a simple one-pot procedure via a hydrothermal approach. Ferric nitrate, palladium acetate, and nickel nitrate were dissolved in water together with glucose, and the mixture was heated in an autoclave. The Fe3O4@Pd@Ni/C nanocomposite was characterized via XRD, TEM, FE-SEM, VSM, EDS, and XPS studies. The catalytic abilities of the Fe3O4@Pd@Ni/C nanocomposite were investigated for the synthesis of distyrylbenzene and 9,10-distyrylanthracene derivatives. This method shows obvious advantages, such as the recyclability of the catalyst, simple experimental operation, and the obtaining of good to excellent yields.
- Shafie, Habiballah,Niknam, Khodabakhsh
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supporting information
p. 11697 - 11704
(2021/07/12)
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- Effects of new NHC derivatives as ligands in the Suzuki–Miyaura reaction
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A series of NHC-derivative ligands was synthesized from bisbenzimidazole salts as the precursor of N-heterocyclic carbene with chalcogens, carbon disulfide, and phenyl isothiocyanate reagents. These new ligands were used in the Suzuki–Miyaura cross-coupling reaction in the presence of palladium(II) acetate. Particularly, it was observed a remarkable ligand activity with tellurourea (5).
- Y?lmaz, ülkü,Kü?ükbay, Hasan
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supporting information
p. 1184 - 1196
(2021/02/16)
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- Palladium supported on structurally stable phenanthroline-based polymer nanotubes as a high-performance catalyst for the aqueous Suzuki-Miyaura coupling reaction
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Though the Suzuki-Miyaura coupling reaction has intrinsic advantages in organic synthesis, it is still a challenging task to develop a highly active and truly heterogeneous catalyst for the aqueous Suzuki-Miyaura coupling reaction (SMR). In this work, a series of phenanthroline-based polymers (PBPs; PBP1 to PBP8) were synthesized by a simple one-step AlCl3-catalyzed Friedel-Crafts polymerization method. Systematic measurements of PBPs by N2adsorption-desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) show that most of the PBPs have a nanosheet morphology, except PBP8 which has both one-dimensional nanotubular morphology and large surface area (745 m2g?1). Benefitting from the porous nanotube morphology and the two N atoms contained in the phenanthroline unit of the polymer structure, polymer PBP8 shows adsorption effects and strong chelating stabilization on the Pd active metal (size, 2-5 nm). The Pd/PBP8 catalyst exhibits superior catalytic activity within 2 h (TOF value: 3077 h?1) and reusability (7 cycles) in the SMR with typical reactants such as bromobenzene, phenylboronic acid and the base of K3PO4.3H2O at 30 °C in a solvent mixture of water and ethanol (VH2O?:?Vethanol= 3?:?2).
- Yang, Didi,Wang, Shuhui,Dan, Ting,Gao, Dashuang,Au, Chaktong,Zhang, Wanju,Zhang, Yan
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p. 12120 - 12128
(2021/07/19)
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- METHOD FOR SYNTHESIZING ORGANIC MAGNESIUM COMPOUND, METHOD FOR SYNTHESIZING ORGANIC BORONIC ACID COMPOUND, AND COUPLING METHOD
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An object is to establish a technology with which an organic magnesium compound can be easily and efficiently synthesized at a low cost with few steps that do not involve a complex chemical method. A method for synthesizing an organic magnesium compound includes, in a reaction solvent, reacting an organic halide represented by General Formula I (Ra—Xa) with a dispersion product obtained by dispersing sodium in a dispersion solvent to obtain an organic sodium compound represented by General Formula II (Ra—Na), and reacting the obtained organic sodium compound with a magnesium halide represented by General Formula III (Mg—(Xb)2) to obtain an organic magnesium compound represented by General Formula IV (Ra—Mg—Xb).
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Paragraph 0016; 0082-00841
(2021/03/13)
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- Cobalt-Catalyzed Coupling of Aryl Chlorides with Aryl Boron Esters Activated by Alkoxides
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The cobalt-catalyzed Suzuki biaryl cross-coupling of aryl chloride substrates with aryl boron reagents, activated with more commonly used bases, remained a significant unmet challenge in the race to replace platinum group metal catalysts with Earth-abundant metal alternatives. We now show that this highly desirable process can be realized using alkoxide bases, provided the right counterion is employed, strict stoichiometric control of the base is maintained with respect to the aryl boron reagent, and the correct boron ester is selected. Potassium tert-butoxide works well, but any excess of the base first inhibits and then poisons the catalyst. Lithium tert-butoxide performs very poorly, while even catalytic amounts of lithium additives also poison the catalyst. Meanwhile, a neopentane diol-based boron ester is required for best performance. As well as delivering this sought-after transformation, we have undertaken detailed mechanistic and computational investigations to probe the possible mechanism of the reaction and help explain the unexpected experimental observations.
- Tailor, Sanita B.,Manzotti, Mattia,Smith, Gavin J.,Davis, Sean A.,Bedford, Robin B.
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p. 3856 - 3866
(2021/04/07)
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- Experimental and Computational Studies towards Chemoselective C?F over C?Cl Functionalisation: Reversible Oxidative Addition is the Key
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Catalytic cross-coupling is a valuable tool for forming new carbon-carbon and carbon-heteroatom bonds, allowing access to a variety of structurally diverse compounds. However, for this methodology to reach its full potential, precise control over all competing cross-coupling sites in poly-functionalised building blocks is required. Carbon-fluorine bonds are one of the most stable bonds in organic chemistry, with oxidative addition at C?F being much more difficult than at other C-halide bonds. As such, the development of methods to chemoselectively functionalise the C?F position in poly-halogenated arenes would be very challenging if selectivity was to be induced at the oxidative addition step. However, metal-halide complexes exhibit different trends in reactivity to the parent haloarenes, with metal-fluoride complexes known to be very reactive towards transmetalation. In this current work we sought to exploit the divergent reactivity of Ni?Cl and Ni?F intermediates to develop a chemoselective C?F functionalisation protocol, where selectivity is controlled by the transmetalation step. Our experimental studies highlight that such an approach is feasible, with a number of nickel catalysts shown to facilitate Hiyama cross-coupling of 1-fluoronapthalene under base free conditions, while no cross-coupling with 1-chloronapthalene occurred. Computational and experimental studies revealed the importance of reversible C?Cl oxidative addition for the development of selective C?F functionalisation, with ligand effects on the potential for reversibility also presented.
- Jacobs, Emily,Keaveney, Sinead T.
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p. 637 - 645
(2020/12/07)
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- Pd Nanoparticles Embedded Into MOF-808: Synthesis, Structural Characteristics, and Catalyst Properties for the Suzuki–Miyaura Coupling Reaction
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Abstract: A heterogeneous single-site catalyst Pd@MOF-808 was successfully synthesized by water-based, green synthesis procedure. The catalytic experiments exhibited the Pd@MOF-808 promoted efficiently the Suzuki–Miyaura coupling reaction without the assistance of organic phosphine ligands at atmospheric pressure conditions. The catalyst also could be applied in the gram-scale synthesis of industrially anti-inflanmatory analgestic Fenbufen. Graphic Abstract: [Figure not available: see fulltext.]
- Li, Tang,Pang, Wan,Wang, Jie,Zhang, Xiaoli,Zhao, Zesheng
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- N-Aroylsulfonamide-Photofragmentation (ASAP)-A Versatile Route to Biaryls
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The photochemical fragmentation of N-aroylsulfonamides 9 (ASAP) is a powerful method for the preparation of various biaryls. Compounds 9 are easily accessible in two steps from amines by treatment with arenesulfonyl chlorides and aroyl chlorides. Many of these compounds were prepared for the first time. The irradiation takes place in a previously developed continuous-flow reactor using inexpensive UVB or UVC fluorescent lamps. Isocyanates and sulphur dioxide are formed as the only by-products. The ASAP tolerates a variety of functional groups and is even suited for the preparation of phenylnaphthalenes and terphenyls. The ASAP mechanism was elucidated by interaction of photophysical and quantum chemical (DFT) methods and revealed a spirocyclic biradical as key intermediate.
- Wessig, Pablo,Krebs, Saskia
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supporting information
p. 6367 - 6374
(2021/09/29)
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- Tris-NHC-propagated self-supported polymer-based Pd catalysts for heterogeneous C-H functionalization
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Three-dimensionally propagated imidazolium-containing mesoporous coordination polymer and organic polymer-based platforms were successfully exploited to develop single-site heterogenized Pd-NHC catalysts for oxidative arene/heteroarene C-H functionalization reactions. The catalysts were efficient in directed arene halogenation, and nondirected arene and heteroarene arylation reactions. High catalytic activity, excellent heterogeneity and recyclability were offered by these systems making them promising candidates in the area of heterogeneous C-H functionalization, where efficient catalysts are still scarce.
- Choudhury, Joyanta,Dutta, Tapas Kumar,Mandal, Tanmoy,Mohanty, Sunit
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supporting information
p. 10182 - 10185
(2021/10/12)
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- Feeding Carbonylation with CO2via the Synergy of Single-Site/Nanocluster Catalysts in a Photosensitizing MOF
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Solar-driven carbonylation with CO2 replacing toxic CO as a C1 source is of considerable interest; however it remains a great challenge due to the inert CO2 molecule. Herein, we integrate cobalt single-site and ultrafine CuPd nanocluster catalysts into a
- Fu, Shanshan,Guo, Guang-Chen,Guo, Song,Lu, Tong-Bu,Yao, Shuang,Yuan, Wenjuan,Zhang, Zhi-Ming
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p. 20792 - 20801
(2021/12/14)
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- Biogenic synthesis of palladium nanoparticles using Boswellia sarrata and their applications in cross-coupling reactions
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A facile and green route for biogenic synthesis of palladium nanoparticles (PdNPs) using aqueous extract of nontoxic and renewable Boswellia sarrata leaves is reported. The as-synthesized PdNPs were systematically characterized by using ultraviolet (UV)–visible spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The PdNPs were crystalline and cubic in nature with average particle size of ~6 nm and successfully employed as heterogeneous catalyst in the Suzuki–Miyaura and Mizoroki–Heck cross-coupling reactions. The PdNPs could be recycled up to five times with modest change in the catalytic activity.
- Arde, Satyanarayan M.,Rashinkar, Gajanan S.,Jadhav, Sanjay N.,Patil, Audumbar D.,Salunkhe, Rajashri S.
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- Highly effective cellulose supported 2-aminopyridine palladium complex (Pd(II)-AMP-Cell?Al2O3) for Suzuki-Miyaura and Mizoroki–Heck cross-coupling
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In the present work, a novel, highly efficient, retrievable organo–inorganic hybrid heterogeneous catalyst (Pd(II)-AMP-Cell?Al2O3) has been prepared by covalent grafting of 2-aminopyridine on chloropropyl modified cellulose-alumina composite followed by complexation with palladium acetate. The catalyst was characterized by techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), inductive coupled plasma-atomic emission spectroscopy (ICP-AES) and thermo gravimetric analysis (TGA). The catalyst has been successfully employed in Suzuki-Miyaura as well as Mizoroki–Heck cross-coupling reactions. The reactions proceed smoothly resulting in the high yields of cross-coupling products (81 to 95%) within short reaction times. The catalyst can be efficiently recovered by simple filtration and reused for multiple cycles without considerable loss in the catalytic activity. The key-features of the present protocol include mild reaction conditions, simple work-up procedure, high stability of the catalyst, high turnover number (TON) and frequency (TOF), ease recovery and reusability of the catalyst.
- Mhaldar, Pradeep,Pore, Dattaprasad,Rashinkar, Gajanan,Vibhute, Sandip
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- L-lysine-Pd Complex Supported on Fe3O4 MNPs: a novel recoverable magnetic nanocatalyst for Suzuki C-C Cross-Coupling reaction
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In this work, L-lysine-Pd Complex, immobilized onto the surface of Fe3O4 MNPs, was successfully prepared via simple and inexpensive procedure. The prepared nanocatalyst was considered as a robust and clean nano-reactor catalyst for the Suzuki and Heck C-C Cross-Coupling reactions in water as the green condition. This eco-friendly heterogeneous catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), X-Ray Diffractometer (XRD), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma atomic emission spectroscopy (ICP), X-ray mapping, BET, thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) techniques. The use of a green medium, easy separation and workup, excellent reusability of the nanocatalyst and short reaction time are some outstanding advantages of this method.
- Ashraf, Muhammad Aqeel,Liu, Zhenling,Zhang, Dangquan,Alimoradi, Ashkan
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- Selective Mechanochemical Monoarylation of Unbiased Dibromoarenes by in Situ Crystallization
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Palladium-catalyzed Suzuki-Miyaura cross-coupling reactions of liquid, unbiased dibromoarenes under mechanochemical conditions selectively afford the monoarylated products. The lower reactivity of the crystalline monoarylated products relative to the liquid starting materials should be attributed predominantly to the low diffusion efficiency of the former in the reaction mixture, which results in a selective monoarylation. The present study sheds light on a novel approach using in situ phase transitions in solids to design selective organic transformations that are difficult to achieve via conventional solution-based synthesis.
- Seo, Tamae,Kubota, Koji,Ito, Hajime
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supporting information
p. 9884 - 9889
(2020/05/19)
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- Synthesis of a Cellulosic Pd(salen)-Type Catalytic Complex as a Green and Recyclable Catalyst for Cross-Coupling Reactions
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Abstract: A green recyclable cellulose-supported Pd(salen)-type catalyst was synthesized through sequential three steps: chlorination with thionyl chloride, modification by ethylenediamine, and the formation of Schiff base with salicylaldehyde to immobilize palladium chloride through multiple binding sites. This novel heterogeneous cellulosic Pd(salen)-type catalytic complex was fully characterized by FT-IR, SEM, TEM, XPS, ICP-AES and TG. The traditional cross-coupling chemistry, such as Suzuki, Heck, Sonogashira, Buchwald–Hartwig amination and etherification, was then investigated in the presence of the above cellulose-palladium nanoparticle. Studies have shown that the synthesized catalyst shows high activity and efficiency for all types of transformations, providing the corresponding carbon–carbon or carbon–heteroatom coupling products in a general and mild manner. Furthermore, the catalyst demonstrates high to excellent yields and is easily recycled by simple filtration for up to twelve cycles without any significant loss of catalytic activity. Graphic Abstract: [Figure not available: see fulltext.]
- Sun, Peng,Yang, Jiaojiao,Chen, Chunxia,Xie, Kaijun,Peng, Jinsong
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p. 2900 - 2910
(2020/03/31)
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- CeO2/Pd Nanoparticles Incorporated Fly Ash Zeolite: An Efficient and Recyclable Catalyst for Csp2-Csp2 Bond Formation Reactions
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The catalytic activity of CeO2 and palladium nanoparticles supported fly ash zeolite (CeO2/Pd@FAZ) for Csp2-Csp2 bond formation was studied. CeO2/Pd@FAZ was characterized by FTIR, XRD, EDAX and TEM studies. In the Suzuki-Miyauracross-coupling reaction, biphenyl derivatives with excellent yields were obtained, and the reaction conditions were optimized. The catalytic activity was explored using a wide variety of diversely substituted aryl bromides and chlorides with aryl boronic acid under optimized reaction conditions. The recyclability of the catalyst was established for three cycles, with the conversion rate from 99 to 40percent, which gained the advantage of heterogeneous catalysis.
- Sheeba Thavamani, Seth,Sudharsan, Murugesan,Santhana Mariya, Anitha,Suresh, Devarajan,Jose Amali, Arlin,Rajeswari, Sanniyasi,Peter Amaladhas, Thomas
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- Palladium (II)–Salan Complexes as Catalysts for Suzuki–Miyaura C–C Cross-Coupling in Water and Air. Effect of the Various Bridging Units within the Diamine Moieties on the Catalytic Performance
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Water-soluble salan ligands were synthesized by hydrogenation and subsequent sulfonation of salens (N,N’-bis(slicylidene)ethylenediamine and analogues) with various bridging units (linkers) connecting the nitrogen atoms. Pd (II) complexes were obtained in reactions of sulfosalans and [PdCl4]2?. Characterization of the ligands and complexes included extensive X-ray diffraction studies, too. The Pd (II) complexes proved highly active catalysts of the Suzuki–Miyaura reaction of aryl halides and arylboronic acid derivatives at 80 ?C in water and air. A comparative study of the Pd (II)–sulfosalan catalysts showed that the catalytic activity largely increased with increasing linker length and with increasing steric congestion around the N donor atoms of the ligands; the highest specific activity was 40,000 (mol substrate) (mol catalyst × h)?1. The substrate scope was explored with the use of the two most active catalysts, containing 1,4-butylene and 1,2-diphenylethylene linkers, respectively.
- Bunda, Szilvia,Joó, Ferenc,Kathó, ágnes,Udvardy, Antal,Voronova, Krisztina
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supporting information
(2020/09/18)
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- Nickel(ii) N-heterocyclic carbene complexes as efficient catalysts for the Suzuki—Miyaura reaction
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Catalytic activity of nickel(ii) and palladium(ii) N-heterocyclic carbene (NHC) complexes derived from imidazole, benzimidazole, and 1,2,4-triazole was comparatively evaluated in the cross-coupling reactions of aryl halides with arylboronic acids. Readily available nickel bis-NHC complexes (NHC)2NiX2 (X = Cl, Br, or I) exhibited the activity comparable to that of the structurally related palladium complexes and, consequently, can be applied as efficient catalysts for the Suzuki—Miyaura reaction.
- Astakhov, A. V.,Chernyshev, V. M.,Pasyukov, D. V.,Soliev, S. B.
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p. 683 - 690
(2020/05/04)
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- Immobilized Pd on Eggshell Membrane: A powerful and recyclable catalyst for Suzuki and Heck cross-coupling reactions in water
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A stable heterogeneous palladium catalysts, the waste eggshell membrane (ESM) anchored Pd complex, was synthesized by a simple and green technique. The catalyst obtained can display an outstanding catalytic activity for Suzuki and Heck coupling reactions in water media. The reactions of various aryl halides with aryl boronic acids and terminal alkenes provided the corresponding products in moderate to excellent yields. More importantly, this novel and efficient catalyst with high stability can be easily reused for at least twelve times with no decrease of the catalytic activity, performing an endurable and wide tolerance of the substrates. Facile synthesis, high catalytic activity, and recyclability make these catalysts interesting for further studies.
- Wu, Shang,Jiang, Hongyan,Zhang, Hong,Zhao, Lianbiao,Yuan, Peilin,Zhang, Ying,Su, Qiong,Wang, Yanbin,Wu, Lan,Yang, Quanlu
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- A Convoluted Polyvinylpyridine-Palladium Catalyst for Suzuki-Miyaura Coupling and C?H Arylation
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The development of highly active and reusable supported catalysts for Suzuki-Miyaura coupling and catalytic C?H arylation is important for fundamental and applied chemistry, with these reactions being used to produce medical compounds and functional materials. Herein, we found that a mesoporous composite made of a linear poly(4-vinylpyridine) and tetrachloropalladate acted as a dual-mode catalyst for a variety of cross-coupling reactions, with both Pd nanoparticles and a Pd complex catalyst being observed under different conditions. The polyvinylpyridine-palladium composite 1 was readily prepared via the molecular convolution of poly(4-vinylpyridine) and sodium tetrachloropalladate to provide a hardly soluble polymer-metal composite. The Suzuki-Miyaura coupling and the C?H arylation of aryl chlorides and bromides with arylboronic acids, thiophenes, furans, benzene, and anisole proceeded in the presence of 0.004 mol% (40 mol ppm) to 1 mol% Pd of 1 to afford the corresponding coupling products in high yields. Furthermore, the catalyst was reused without an appreciable loss of activity. Pharmaceutical compounds and functional materials were synthesized via the coupling reactions. N2 gas adsorption/desorption analysis indicated that the catalyst had a mesoporous nature, which played a crucial role in the catalysis. In the Suzuki-Miyaura couplings, in situ generated palladium nanoparticles in the polymer matrix were catalytically active, while a polymeric Pd(II) complex was crucial in the C?H arylations. These catalytic species were investigated via XAFS, XPS, far-infrared absorption, and Raman spectroscopies, as well as DFT calculations. (Figure presented.).
- Ohno, Aya,Sato, Takuma,Mase, Toshiaki,Uozumi, Yasuhiro,Yamada, Yoichi M. A.
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supporting information
p. 4687 - 4698
(2020/09/07)
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- Palladium Nanoparticles Anchored on Thiol Functionalized Xylose Hydrochar Microspheres: An Efficient Heterogeneous Catalyst for Suzuki Cross-Coupling Reactions
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Abstract: Novel thiol functionalized xylose hydrochar microspheres supported palladium nanoparticles (C–SH–Pd) were synthesized by gentle heating of palladium (II) acetate and thiol functionalized xylose hydrochar (C–SH) in ethanol. The as-prepared C–SH–Pd exhibited high catalytic activity towards Suzuki reactions with a yield of high up to 100%. Moreover, it could be reused for at least five times without heavily loss of the catalytic activity. The amount of palladium entrapped on C-SH microspheres was measured by AAS and found to be 1.42?mmol/g. Leaching studies showed that the filtrate contained less than 0.2?ppm Pd. Due to the superior catalytic performance and stability of the C–SH–Pd catalyst, it can be exploited in other cross coupling reactions in the long run. Graphic Abstract: [Figure not available: see fulltext.].
- Huang, Pingquan,Zeng, Xiaoyan,Du, Fan,Zhang, Lei,Peng, Xinwen
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p. 1011 - 1019
(2019/11/13)
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- Nanocatalosomes as Plasmonic Bilayer Shells with Interlayer Catalytic Nanospaces for Solar-Light-Induced Reactions
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Interest and challenges remain in designing and synthesizing catalysts with nature-like complexity at few-nm scale to harness unprecedented functionalities by using sustainable solar light. We introduce “nanocatalosomes”—a bio-inspired bilayer-vesicular design of nanoreactor with metallic bilayer shell-in-shell structure, having numerous controllable confined cavities within few-nm interlayer space, customizable with different noble metals. The intershell-confined plasmonically coupled hot-nanospaces within the few-nm cavities play a pivotal role in harnessing catalytic effects for various organic transformations, as demonstrated by “acceptorless dehydrogenation”, “Suzuki–Miyaura cross-coupling” and “alkynyl annulation” affording clean conversions and turnover frequencies (TOFs) at least one order of magnitude higher than state-of-the-art Au-nanorod-based plasmonic catalysts. This work paves the way towards next-generation nanoreactors for chemical transformations with solar energy.
- Cho, Yoon-Kyoung,Dubbu, Sateesh,Kim, Inki,Koo, Jung Hun,Kumar, Amit,Kumar, Sumit,Kumari, Nitee,Kwon, Taewan,Lee, In Su,Lim, Jongwon,Rho, Junsuk
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supporting information
p. 9460 - 9469
(2020/05/04)
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- Synthesis of Enaminone-Pd(II) Complexes and Their Application in Catalysing Aqueous Suzuki-Miyaura Cross Coupling Reaction
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A series of Pd(II)-enaminone complexes, termed Pd(eao)2, have been synthesized and characterized. The investigation on the catalytic activities of these new Pd(II)-reagents has proved that the Pd(eao)2-1 possesses excellent catalytic activity for the Suzuki- Miyaura cross coupling reactions of aryl bromides/chlorides with aryl/vinyl boronic acids in the environmentally benign media of aqueous PEG400 at low loading (5 mol‰). The superiority of this Pd(II)-reagent to those commercial Pd(II) and Pd(0) catalysts in catalyzing the reactions has been confirmed by parallel experiments. What's more, Pd(eao)2-2 has been found as a practical catalyst for the homo-coupling reactions of aryl boronic acids.
- Fu, Leiqing,Cao, Xiaoji,Wan, Jie-Ping,Liu, Yunyun
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p. 254 - 258
(2020/01/25)
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- Magnetic nanoparticles-supported palladium catalyzed Suzuki-Miyaura cross coupling
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A new magnetic nanoparticles-supported palladium(II) nanomagnetic catalyst (Pd-AcAc-Am-Fe3O4?SiO2) was synthesized and characterized using attenuated total reflectance infrared spectroscopy (ATR-IR), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The nanomagnetic catalyst was used as an efficient catalyst for the Suzuki-Miyaura cross-coupling of various aryl bromides/chlorides/iodides with phenylboronic acid. The effect of varying solvents, base, temperature, reaction time and catalyst amount on the performance of the Suzuki-Miyaura cross-coupling is investigated. The notable advantages of heterogeneous nanomagnetic catalyst are excellent yields, mild reaction conditions, short reaction time, easy magnetic work-up and recyclability. Moreover, the new nanomagnetic catalyst could be easily recovered with an external magnet and reused at least six times without significant loss of its catalytic activity.
- Vibhute, Sandip P.,Mhaldar, Pradeep M.,Shejwal, Rajendra V.,Pore, Dattaprasad M.
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supporting information
(2020/01/21)
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- Small organic molecules with tailored structures: Initiators in the transition-metal-free C-H arylation of unactivated arenes
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Simple, small organic molecules containing nitrogen and oxygen atoms in their structures have been disclosed to catalyze transition-metal-free C-H arylation of unactivated arenes with aryl iodides in the presence of tBuOK. In this article, an optimized catalytically active molecule, (2-(methylamino)phenyl)methanol, was designed. A broad range of aryl iodides could be converted into the corresponding arylated products at 100 °C over 24 h with good to excellent yields. Mechanistic experiments verified that radicals participated in this catalytic transformation and that the cleavage of the aromatic C-H bond was not the rate determining step. A K+ capture experiment by 18-crown-6 emphasized the significance of the cation species of the strong base. Fourier transform infrared spectroscopy proved that the catalytic system was activated by the hydrogen bonds between small organic molecules and tBuOK. Also, a clear mechanism was proposed. This transition-metal-free method affords a promising system for efficient and inexpensive synthesis of biaryls via a user-friendly approach, as confirmed by scale-up experiments.
- Chen, Suqing,Chen, Wenjun,Chen, Yu,Liu, Zhenghui,Mu, Tiancheng,Wang, Peng,Yan, Zhenzhong
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p. 14500 - 14509
(2020/04/27)
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- Organocatalyst in Direct C(sp2)-H Arylation of Unactivated Arenes: [1-(2-Hydroxyethyl)-piperazine]-Catalyzed Inter-/Intra-molecular C-H Bond Activation
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This article describes the identification of 1-(2-hydroxyethyl)-piperazine as a new, cost-effective, highly efficient organocatalyst, which promotes both inter- A nd intra-molecular direct C(sp2)-H arylations of unactivated arenes in the presence of potassium tert-butoxide. While the inter-molecular C-H arylation of unactivated benzenes with aryl halides (Ar-X; X = I, Br, Cl) toward biaryl syntheses underwent smoothly in the presence of only 10 mol percent organocatalyst, the intra-molecular C-H arylation catalytic system composed of 40 mol percent each of the catalyst and the additive (4-dimethylaminopyridine (DMAP)). The novel catalyst was also able to perform both inter- A nd intra-molecular direct arylations simultaneously in a single pot. The mechanistic studies confirmed the involvement of aryl radical anions and proceeded via a single-electron-transfer (SET) mechanism. The large substrate scope, high functional group tolerance, competition experiments, gram-scale synthesis, and kinetic studies further highlight the importance and versatile nature of the methodology as well as the compatibility of the new catalyst. To the best of our knowledge, this is the first report on any organocatalyst that reported detailed investigations of both inter- A nd intra-molecular direct C(sp2)-H arylations of unactivated arenes in a single representation.
- Yadav, Lalit,Tiwari, Mohit K.,Shyamlal, Bharti Rajesh Kumar,Chaudhary, Sandeep
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p. 8121 - 8141
(2020/07/16)
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- Aryl Fluoride Activation through Palladium-Magnesium Bimetallic Cooperation: A Mechanistic and Computational Study
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Herein is described a mechanistic study of a palladium-catalyzed cross-coupling of aryl Grignard reagents to fluoroarenes that proceeds via a low-energy heterobimetallic oxidative addition pathway. Traditional oxidative additions of aryl chlorides to Pd complexes are known to be orders of magnitude faster than with aryl fluorides, and many palladium catalysts do not activate aryl fluorides at all. The experimental and computational studies outlined herein, however, support the view that at elevated Grignard/ArX ratios (i.e., 2.5:1), a Pd-Mg heterobimetallic mechanism predominates, leading to a remarkable decrease in the energy required for Ar-F bond activation. The heterobimetallic transition state for the C-X bond cleavage is proposed to involve simultaneous Pd backbonding to the arene and Lewis acid activation of the halide by Mg to create a low-energy transition state for oxidative addition. The insights gained from this computational study led to the development of a phosphine ligand that was shown to be similarly competent for Ar-F bond activation.
- Wu, Chen,McCollom, Samuel P.,Zheng, Zhipeng,Zhang, Jiadi,Sha, Sheng-Chun,Li, Minyan,Walsh, Patrick J.,Tomson, Neil C.
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p. 7934 - 7944
(2020/08/21)
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- Tetrabutylphosphonium 4-ethoxyvalerate as a biomass-originated media for homogeneous palladium-catalyzed Hiyama coupling reactions
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The introduction of a biomass-derived ionic liquid into the Hiyama coupling reactions, which has been considered as a powerful tool for the synthesis of symmetrically and non-symmetrically substituted biaryl structures, could further control or even reduce the environmental impact of this transformation. It was shown that tetrabutylphosphonium 4-ethoxyvalerate, a γ-valerolactone-based ionic liquid, can be utilized as an alternative solvent to create carbon–carbon bonds between aryl iodides and functionalized organosilanes in the presence of 1?molpercent Pd under typical Hiyama conditions (130?°C, 24?h, tetrabutylammonium fluoride activator). A comparison of different ionic liquids was performed, and the effects of the catalyst precursor and the moisture content of the reaction mixture on the activity of the catalyst system were investigated. The functional group tolerance was also studied, resulting in 15 cross-coupling products (3a–o) with isolated yields of 45–72percent and excellent purity (' 98percent).
- Orha, László,Papp, ábrahám,Tukacs, József M.,Kollár, László,Mika, László T.
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p. 4593 - 4598
(2020/07/28)
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- Nickel(II)/N-Heterocyclic Carbene Catalyzed Desulfinylative Arylation by C?S Cleavage of Aryl Sulfoxides with Phenylboronic Acids
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Suzuki-Miyaura coupling of haloarenes is the most widely used protocol for the synthesis of biphenyls. Organosulfur compounds are promising electrophiles since they are abundant in nature and versatile in organic synthesis. We report here the desulfinylative Suzuki-Miyaura coupling of aryl sulfoxides with phenylboronic acids using bench-stable nickel/5-(2,4,6-triisopropylphenyl)imidazolylidene[1,5-a]pyridines as the catalyst. The ligands are readily prepared from common commercial chemicals. The method is applicable to both symmetric and unsymmetric aryl sulfoxides, and a range of biphenyls bearing various functional groups were obtained in up to 94% yield. (Figure presented.).
- Yi, Xiaowen,Chen, Kai,Guo, Junjun,Chen, Wei,Chen, Wanzhi
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supporting information
p. 4373 - 4377
(2020/07/27)
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