- Seven-membered Pd(II) complexes containing symmetric phosphorus ylides: Synthesis, characterization and high catalytic activity toward Suzuki cross-coupling reactions
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The reaction of 1,2-bis(diphenylphosphino)ethane (dppe) with various ketones in acetone produces the new phosphonium salts [RC(O)CH 2PPh2(CH2)2PPh2CH 2C(O)R]X2 (R = 2-naphtyl, X
- Sabounchei, Seyyed Javad,Panahimehr, Mohammad,Ahmadi, Mohsen,Akhlaghi, Fateme,Boscovic, Collete
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- Preparation of Co-Pd bimetallic nanoparticles encapsulated in bamboo-like N-doped mesoporous carbon by a facile one-pot method for green Suzuki coupling
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CoPd bimetallic nanoparticles (NPs) were successfully encapsulated in bamboo-like N-doped mesoporous carbon (bNMC) via a facile one-pot method through combination of dissolving chelation and carbonization reactions. The morphology, structure and composition of CoPd-bNMC was verified by detailed characterization including SEM, TEM, EDX, XPS, XRD, N2 adsorption–desorption, VSM, and ICP. The as-prepared CoPd/bNMC showed excellent activity and selectivity for Suzuki coupling under mild and green condition. Though the Pd content of CoPd/bNMC was half of Pd/bNMC, the catalytic performance of CoPd/bNMC was almost the same with Pd/bNMC, which was caused by its special bimetallic alloy structure, high BET surface area and pore volume. Importantly, CoPd/bNMC with magnetic property can be separated using external magnetic field and reused for five consecutive runs in the reaction of Suzuki crossing without significant loss of activity. It was found the Pd content only showed slight loss (2.3?wt.%) after five reused reactions, which was because CoPd bimetallic NPs were inside the bamboo-like N-doped mesoporous carbon.
- Wu, Li,Long, Yu,Ma, Jiantai,Lu, Gongxuan
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- Easy conversion of nitrogen-rich silk cocoon biomass to magnetic nitrogen-doped carbon nanomaterial for supporting of Palladium and its application
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In this study, magnetic nitrogen-doped carbon (MNC) was fabricated through facile carbonization and activation of natural silk cocoons containing nitrogen and then combined with Fe3O4 nanoparticles to create a good support material for palladium. Palladium immobilization on the support resulted in the formation of magnetic nitrogen-doped carbon-Pd (MNC-Pd). The prepared heterogeneous catalyst was well characterized using FT-IR, TGA, EDX, FE-SEM, XRD, VSM, and ICP-OES techniques. Thereafter, the synthesis of biaryl compounds was conducted to investigate the catalyst performance via the reaction of aryl halides and phenylboronic acid. Further, the catalyst could be used and recycled for six consecutive runs without any significant loss in its activity.
- Akbarzadeh, Parisa,Koukabi, Nadiya
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- Recyclable and ligandless suzuki coupling catalyzed by carbon nanotube-supported palladium nanoparticles synthesized in supercritical fluid
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Carbon nanotube-supported palladium nanoparticles prepared by a supercritical fluid deposition method show high activities for catalyzing Suzuki coupling reactions, and the catalysts can be recycled and reused at least six times without losing activity. Copyright Taylor & Francis Group, LLC.
- Pan, Horng-Bin,Yen, Clive H.,Yoon, Byunghoon,Sato, Masaki,Wai, Chien M.
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- Synthesis, transition metal chemistry and catalytic reactions of ferrocenylbis(phosphonite), [Fe{C5H4P(OC6H 3(OMe-o)(C3H5-p))2}2]
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The new metalloligand ferrocenylbis(phosphonite), [Fe(C5H 4PR2)2 (R = OC6H3(OMe-o) (C3H5-p))], (2), is synthesized by the reaction of bis(dichlorophosphino)ferrocene Fe(C5H4PCl 2)2 (1) with 4-allyl-2-methoxyphenol. The reactions of 2 with H2O2 and elemental sulfur or selenium afforded bischalcogenides, [Fe{C5H4P(E)(OC6H 3(OMe-o)(C3H5-p))2}2] (3, E = O; 4, E = S; 5, E = Se), in good yield. The bis(phosphonite) reacts with group 6 metal carbonyls and group 10 metal dichloride precursors to produce the chelate complexes [{M(CO)4}Fe{C5H4P(OC 6H3(OMe-o)(C3H5-p)) 2}2}] (6, M = Mo; 7, M = W) and [(MCl2) Fe{C5H4P(OC6H3(OMe-o)(C 3H5-p))2}2] (8, M = Pd; 9, M = Pt). The palladium(ii) complex [(PdCl2)Fe{C5H 4P(OC6H3(OMe-o)(C3H 5-p))2}2] (8) is an efficient catalyst for the Suzuki-Miyaura cross-coupling reactions (TON up to 1.5 × 105). The reaction of 2 with one equivalent of [RuCl2(η6-p- cymene)]2 yielded the binuclear complex [{Ru2Cl 4(η6-p-cymene)2}Fe{C5H 4P(OC6H3(OMe-o)(C3H 5-p))2}2] (12) in good yield. Treatment of 2 with copper chloride in a 1:1 or 1:2 molar ratio resulted in the formation of a binuclear complex, [{(CuCl)Fe{C5H4P(OC6H 3(OMe-o)(C3H5-p))2} 2}2] (13), whereas a similar reaction of 2 with CuBr and CuI in a 1:2 or 1:2.5 molar ratio yielded the novel butterfly-like deca-nuclear complexes [Cu5(μ-X)5{Fe{C5H 4P(OC6H3(OMe-o)(C3H 5-p))2}2}2]2 (14, X = Br; 15, X = I). The reaction of 2 with two equivalents of [AuCl(SMe2)] afforded the digold complex [(AuCl)2Fe{C5H 4P(OC6H3(OMe-o)(C3H 5-p))2}2] (16), with the ligand exhibiting bridged-bidentate mode of coordination. Additionally, some complexes were studied by cyclic voltammetry. The crystal structures of complexes 8, 9, 12, 15 and 16 were determined using X-ray diffraction studies.
- Rao, Sowmya,Mague, Joel T.,Balakrishna, Maravanji S.
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- 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.
- Mirza-Aghayan, Maryam,Mohammadi, Marzieh,Boukherroub, Rabah
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- Synthesis of Substituted Thiophenes through Dehydration and Heterocyclization of Alkynols
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A protocol was described for obtaining a variety of substituted thiophenes with functional potential via metal-free dehydration and sulfur cyclization of alkynols with elemental sulfur (S8) or EtOCS2K in moderate-to-good yields. The method provides the base-free generation of a trisulfur radical anion (S3?-) and its addition to alkynes as an initiator. This research broadens the applications of S3?-in the synthesis of sulfur-containing heterocycles.
- Chen, Lu,Chen, Zebin,Huang, Yubing,Ji, Xiaoliang,Li, Jiaming,Li, Jian,Li, Yibiao,Liu, Qiang,Liu, Yang
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supporting information
p. 3555 - 3566
(2022/03/14)
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- Lipids as versatile solvents for chemical synthesis
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Development of safe, renewable, cheap and versatile solvents is a longstanding challenge in chemistry. We show here that vegetable oils and related systems can become prominent solvents for organic synthesis. Suzuki-Miyaura, Hiyama, Stille, Sonogashira and Heck cross-couplings proceed with quantitative yields in a range of vegetable oils, fish oil, butter and waxes used as solvents. Appropriate methodologies for high-throughput screening and sustainable isolation techniques applicable for vegetable oils and related lipids are presented.
- Bayer, Annette,Gevorgyan, Ashot,Hopmann, Kathrin H.
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supporting information
p. 7219 - 7227
(2021/09/28)
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- Molecular engineered palladium single atom catalysts with an M-C1N3subunit for Suzuki coupling
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Single atom catalysis has emerged as a powerful technique for catalysis due to its outstanding performance and atom economy. Controlling the hybridization of the atom with its environment is crucial in determining the selectivity and/or yield of the reaction. However, the single atom environment is usually ill-defined and hard to predict because the pyrolysis process used in preparing SACs damages the original status of the precursors in the catalyst preparation. A molecular engineering approach to synthesize single atom catalysts (SACs) on a heterogeneous template provides a strategy to make SACs with a highly uniform coordinating environment. Herein, we report the preparation of a molecular engineered Pd single atom catalyst with a pre-defined M-N3C1 coordination (Pd-N3C1-SAC) using a structure-rigid Pd-N3C1 porphyrin as the precursor, which shows more efficient Suzuki coupling compared with the SAC with Pd-N4 coordination. The origin of the high activity of the Pd-N3C1-SAC is revealed through density functional theory calculations, where a lower reaction barrier for the rate-determining oxidative addition is identified. This journal is
- Liu, Jia,Chen, Zhongxin,Liu, Cuibo,Zhang, Bao,Du, Yonghua,Liu, Chen-Fei,Ma, Lu,Xi, Shibo,Li, Runlai,Zhao, Xiaoxu,Song, Jingting,Sui, Xin Zhi,Yu, Wei,Miao, Ling,Jiang, Jianjun,Koh, Ming Joo,Loh, Kian Ping
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supporting information
p. 11427 - 11432
(2021/05/19)
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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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- Fe3O4-SAHPG-Pd0 nanoparticles: A ligand-free and low Pd loading quasiheterogeneous catalyst active for mild Suzuki–Miyaura coupling and C-H activation of pyrimidine cores
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This paper reports a green magnetic quasiheterogeneous efficient palladium catalyst in which Pd0 nanoparticles have been immobilized in self-assembled hyperbranched polyglycidole (SAHPG)-coated magnetic Fe3O4 nanoparticles (Fe3O4-SAHPG-Pd0). This catalyst has been used for effective ligandless Pd catalyzed Suzuki–Miyaura coupling reactions of different aryl halides with substituted boronic acids at room temperature and in aqueous media. Herein, SAHPG is used as support; it also acts as a reducing agent and stabilizer to promote the transformation of PdII to Pd0 nanoparticles. Also, this environmental friendly quasiheterogeneous catalyst is employed for the first time in the synthesis of new pyrimido[4,5-b]indoles via oxidative addition/C-H activation reactions on the pyrimidine rings, which were obtained with higher yield and faster than when Pd(OAc)2 was used as the catalyst. Interestingly, the above-mentioned catalyst could be recovered in a facile manner from the reaction mixture by applying an external magnet device and recycled several times with no significant decrease in the catalytic activity.
- Azizollahi, Hamid,Eshghi, Hossein,García-López, José-Antonio
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- Magnetic covalently immobilized nickel complex: A new and efficient method for the Suzuki cross-coupling reaction
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In this study, an efficient procedure was reported to prepare Fe3O4@SiO2 magnetic nanoparticles (MNPs) with immobilized nickel NPs. In order to increase the activity of this catalyst, creatine as a ligand with high content of nitrogen atoms was linked onto the magnetic core–shell structure. Then, Ni(II) ions were coordinated on the surface of the silica-coated MNPs and reduced to Ni(0) NPs to obtain the final catalyst. The catalytic activity of the prepared catalyst was studied for the synthesis of biaryl derivatives via the Suzuki–Miyaura cross-coupling reaction in high yields. The catalyst could also be recovered and reused with no loss of activity over five successful runs.
- Keyhaniyan, Mahdi,Khojastehnezhad, Amir,Eshghi, Hossein,Shiri, Ali
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- Green synthesis of Pd/Fe3O4 nanoparticles using Chamomile extract as highly active and recyclable catalyst for Suzuki coupling reaction
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In the present study, we demonstrate the synthesis of a novel biogenic nanocomposite by adorning in situ green synthesized Pd nanoparticles (Pd NPs) over the surface of magnetic nanoparticles by using Chamomileflower extract. It was physicochemically assigned by a number of analytical techniques. The as developed material was catalytically exploited in the synthesis of diverse biaryls via classical Suzuki-Miyaura coupling. Rigourness of the material was further validated by the study of reusability, hot-filtration and leaching test.
- Hamelian, Mona,Kamangar, Sheida Ahany,Karmakar, Bikash,Saremi, Shokoufeh Ghahri,Varmira, Kambiz,Veisi, Hojat,Zohrabi, Arezu
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- Silica-coated magnetic nanoparticles functionalized cobalt complex: a recyclable and efficient catalyst for the C?C bond formation
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In this study, the Co-based catalyst was prepared by cobalt immobilization on the surface of functionalized silica-coated magnetic NPs (Fe3O4@SiO2-CT-Co) as a magnetically core–shell nanocatalyst and characterized by FT-IR, TGA, XRD, VSM, SEM, TEM, EDX, EDX mapping, and ICP techniques and appraised in the Suzuki–Miyaura cross-coupling reaction under mild reaction conditions. The results displayed the superparamagnetic behavior of the Fe3O4 NPs core encapsulated by SiO2 shell, and the size of the particles was estimated about 30?nm. Compared with the previously reported catalysts, the engineered Fe3O4@SiO2-CT-Co catalyst provided perfect catalytic performance for the Suzuki–Miyaura cross-coupling reaction in water as a green solvent and it was much cheaper in the comparison with the traditional Pd-based catalysts. Importantly, the durability of magnetic nanocatalyst was studied and observed that it is stable under the reaction conditions and could be easily reused for at least six successive cycles without any significant decrease in its catalytic activity. Graphic abstract: [Figure not available: see fulltext.]
- Haqjow, Hanif,Raoufi, Farveh
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p. 4113 - 4128
(2021/07/26)
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- Suzuki coupling reactions catalyzed by Schiff base supported palladium complexes bearing the vitamin B6 cofactor
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Novel Schiff bases were synthesized by condensing aromatic amines with pyridoxal-5’-phosphate and characterized by using FT-IR, 1H NMR, and 13C NMR spectroscopic techniques. The resulting Schiff bases were utilized as bidentate ligands, coordinating via imine nitrogen and phenolate oxygen atoms, to stabilize palladium ions. Aryl substituents on imine nitrogen allowed for fine tuning of the stereoelectronic properties of the Schiff bases. The catalytic activity of the selected palladium complexes was investigated in the Suzuki cross-coupling reaction of a series of aryl halides with boronic acids in H2O/EtOH (1:1). Out of four complexes investigated in the cross-coupling reactions, Pd(L8)2, bearing a methoxy substituent on aryl imine, showed the highest activity at low catalyst loading. The scope of the reaction was also investigated with 26 samples.
- Neshat, Abdollah,Gholinejad, Mohammad,?zcan, Hafize,Khosravi, Faezeh,Mobarakeh, Ali Mousavizadeh,Zaim, ?mer
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- Pd salen complex@CPGO as a convenient, effective heterogeneous catalyst for Suzuki–Miyaura and Heck–Mizoroki cross-coupling reactions
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A Pd(II) Schiff base complex supported on graphene oxide nanosheets (Pd(II) salen@CPGO) has been synthesized and characterized by FT-IR, ICP-AES, XRD, SEM/EDX and TEM. The synthesized nanocatalyst has been found to be an efficient heterogeneous catalyst for Suzuki–Miyaura and Heck–Mizoroki coupling reactions. Pd(II) salen@CPGO could be separated and recovered easily from the reaction mixture and recycled several times without a discernible decrease in its catalytic activity. The construction of a solid sheet-supported Pd catalyst would be expected to be a promising system to perform heterogeneous catalytic reactions.
- Ghabdian, Mahdieh,Nasseri, Mohammad Ali,Allahresani, Ali,Motavallizadehkakhky, Alireza
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p. 1713 - 1728
(2018/05/25)
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- Hydrophilic role of deep eutectic solvents for clean synthesis of biphenyls over a magnetically separable Pd-catalyzed Suzuki-Miyaura coupling reaction
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The development of an efficient and sustainable catalytic system for the preparation of biphenyls through the Suzuki-Miyaura coupling reaction is still a great challenge to green chemistry. Encouraging the prevailing challenge, in the present work, a heterogeneous Pd catalyst was synthesized through a green method and used for the production of biphenyls in deep eutectic solvents (DESs) as green reaction media. In order to prepare the catalyst, magnetite-graphene oxide nanocomposite was modified with cellulose via the click reaction and applied as support for Pd nanoparticles. Cellulose acted as both reducing and stabilizing agent for Pd nanoparticles and eliminated the requirement of a reducing agent. The prepared catalyst was characterized by different methods such as FT-IR, EDX, EDX-mapping, XPS, SEM, TEM, XRD, VSM, and ICP-OES analyses. Catalytic properties of the obtained catalyst was explored in the coupling reaction of aryl halides with aryl boronic acids in different hydrophilic and hydrophobic DESs. The presence of cellulose with hydrophilic character on the structure of catalyst offered well dispersion of the catalyst in hydrophilic DESs, which led to enhancement of its catalytic activity. Among various hydrophilic DESs, the DES composed of dimethylammonium chloride and glycerol was verified as the most effective solvent for the preparation of biphenyls. The catalyst was compatible with a variety of substrates, with which all the Suzuki coupling products were achieved in high to excellent yields. Thanks to the low solubility of catalyst and DES in organic solvents, the separated aqueous phase containing both of the catalyst and DES could be readily recovered by evaporating water and reused up to five successive runs with a stable activity. This simple and new separation strategy provided a clean and highly efficient synthetic methodology for the synthesis of various biphenyls. Moreover, hot filtration test efficiently confirmed that the catalyst is heterogeneous and completely stable under reaction conditions.
- Karimi, Sabah,Masteri-Farahani, Majid,Niakan, Mahsa,Shekaari, Hemayat
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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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- Cyclopalladated benzo[h]quinolinate complexes based on stabilized phosphonium-phosphine ylides: Synthesis, characterization, and application as catalyst in aqueous-phase Suzuki-Miyaura reaction
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A series of heteroleptic mononuclear cyclopalladated benzo[h]quinolinate complexes of general formula [Pd(bzq)(Ph2PCH2PPh2C(H)C(O)C6H4-p-R)]ClO4 (bzq = 7,8-benzoquinoline; R = Cl (C1/
- Azadi, Roya,Noorabadi, Fatemeh Esmipour,Samiee, Sepideh
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- A facile and versatile electro-reductive system for hydrodefunctionalization under ambient conditions
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A general electrochemical system for reductive hydrodefunctionalization is described, employing the inexpensive and easily available triethylamine (Et3N) as a sacrificial reductant. This protocol is characterized by facile operation, sustainable conditions, and exceptionally wide substrate scope covering the cleavage of C-halogen, N-S, N-C, O-S, O-C, C-C and C-N bonds. Notably, the selectivity and capability of reduction can be conveniently switched by simple incorporation or removal of an alcohol as a co-solvent.
- Huang, Binbin,Guo, Lin,Xia, Wujiong
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supporting information
p. 2095 - 2103
(2021/03/26)
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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 0093-0101
(2021/02/24)
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- 2-Phosphinoimidazole Ligands: N-H NHC or P-N Coordination Complexes in Palladium-Catalyzed Suzuki-Miyaura Reactions of Aryl Chlorides
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We report the synthesis of two palladium 2-(dialkylphosphino)imidazole complexes and demonstrate their activity as catalysts for Suzuki-Miyaura reactions with (hetero)aryl chlorides at room temperature. Our mechanistic studies demonstrate that these palladium complexes exist as an equilibrium mixture between the P-N coordinated and N-H NHC forms of ligand. Our studies suggest that the N-H NHC form may be important for high catalytic activity in Suzuki-Miyaura reactions with aryl chlorides. These reactions proceed at or near room temperature in good to excellent yields. Heteroaryl chlorides are also reactive at lower catalyst loadings.
- Martinez, Erin E.,Larson, Alexandra J. S.,Fuller, Sydney K.,Petersen, Kathryn M.,Smith, Stacey J.,Michaelis, David J.
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supporting information
p. 1560 - 1564
(2021/05/29)
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- Designing biaryl phosphacyclic ligands: their characterization and evaluation in palladium-catalyzed Suzuki-Miyaura reactions of aryl bromides and chlorides
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Efficient palladium catalyst systems based on the combination of bench stable biaryl phosphacycles and Pd(OAc)2 are described for Suzuki-Miyaura cross-coupling reactions of aryl bromides and chlorides. Notably, the electronically and sterically diametric biaryl phosphacycles allowed facile coupling of sterically hindered and heterocyclic substrates.
- Holzapfel, Cedric W.,Lamola, Jairus L.,Maumela, Munaka Christopher,Moshapo, Paseka T.
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- Pyrazole-Mediated C-H Functionalization of Arene and Heteroarenes for Aryl-(Hetero)aryl Cross-Coupling Reactions
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Herein we introduce a transition-metal-free protocol that involves a commercially available, inexpensive pyrazole molecule to conduct C-C cross-coupling reactions at room temperature via a radical pathway. Using this method, an aryldiazonium salt has been coupled to a wide range of arenes and heteroarenes including benzene, mesitylene, thiophene, furan, benzoxazole to result the corresponding biaryl products. The full reaction mechanism is elucidated along with the crystallographic probation of an active initiator species. A potassium-stabilized deprotonated pyrazole steers single-electron transfer to the substrate and behaves as an initiator for the reaction.
- Kundu, Abhishek,Dey, Dhananjay,Pal, Subhankar,Adhikari, Debashis
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p. 15665 - 15673
(2021/11/16)
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- Aerobic Cu and amine free Sonogashira and Stille couplings of aryl bromides/chlorides with a magnetically recoverable Fe3O4@SiO2 immobilized Pd(II)-thioether containing NHC
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Two value added C–C cross coupling reactions; Sonogashira and Stille couplings were achieved at milder conditions in the catalytic presence of a magnetically recoverable heterogeneous catalyst Fe3O4@SiO2@NHC^SPh-Pd(II). The catalyst was earlier reported for Suzuki-Miyaura reaction, and as an extension of its catalytic efficiency, the Stille and Sonogashira cross coupling reactions under aerobic condition has been explored in present report. The Sonogashira coupling of aryl bromides and terminal alkynes produced an excellent yield (~96% at 0.25 mol% Pd) of the desired coupling product under copper and amines free conditions. Moreover, an excellent Stille coupling of readily available and more latent aryl chlorides and trialkylstannane was obtained (yields up to 95% at 0.25 mol% Pd) in absence of toxic fluorides additives. The broad substrate scope of the catalyst for both the coupling reactions and the magnetically recoverable feature of catalyst make this reaction highly desirable for industrial applications of present heterogeneous catalysis.
- Khandaka, Himanshu,Sharma, Kamal Nayan,Joshi, Raj Kumar
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supporting information
(2021/02/20)
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- Black phosphorus as a metal-free, visible-light-active heterogeneous photoredox catalyst for the direct C-H arylation of heteroarenes
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Black phosphorus (BP) is for the first time employed as a metal-free, heterogeneous photoredox catalyst for the direct C-H arylation of heteroarenes with aryl diazonium salts. The arylated heteroarenes are obtained in moderate to good yields under visible-light illumination, and the protocol is shown to be applicable for the scale-up synthesis.
- Kalay, Erbay,Kü?ükke?eci, Hüseyin,Kilic, Haydar,Metin, ?nder
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supporting information
p. 5901 - 5904
(2020/06/04)
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- Carbazole based Electron Donor Acceptor (EDA) catalysis for the synthesis of biaryl and aryl-heteroaryl compounds
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A highly regioselective, carbazole based Electron Donor Acceptor (EDA) catalyzed synthesis of biaryl and aryl-heteroaryl compounds is described. Various indole and carbazole derivatives were screened for the Homolytic Aromatic Substitution (HAS) reaction. Tetrahydrocarbazole (THC) was very efficient for the HAS transformation and proceeded via a complex formation between diazonium salt and electron rich tetrahydrocarbazole. The UV-Vis spectroscopy technique has been used to confirm the complex formation. The in situ generated EDA complex even in a catalytic amount is found to be efficient for the Single Electron Transfer (SET) process without any photoactivation. Biaryl compounds, 2-phenylfuran, 2-phenylthiophene, and 2-phenylpyrrole and bioactive compounds such as dantrolene and canagliflozin have been synthesized in moderate to excellent yields.
- Annes, Sesuraj Babiola,Ramesh, Subburethinam,Saravanan, Subramanian,Saritha, Rajendhiran
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supporting information
p. 2510 - 2515
(2020/04/15)
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- A facile synthesis of mesoporous graphitic carbon nitride supported palladium nanoparticles as highly effective and reusable catalysts for Stille coupling reactions under mild conditions
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The development of a Stille coupling protocol that is operable under moderate conditions without using a base is highly required for the synthetic organic chemistry community, which requires an efficient nanocatalyst. In this respect, addressed herein is a facile one-pot synthesis of mesoporous graphitic carbon nitride (mpg-CN) supported Pd NPs, denoted as mpg-CN/Pd hereafter, and investigation of their catalytic activity in Stille cross-coupling reactions for the first time. It has been demonstrated that mpg-CN nanosheets can serve as not only a support material but also a stabilizer for the generation of 4.5 nm Pd NPs. The ecofriendly generated heterogeneous nanocatalyst was characterized by TEM, XRD, XPS, BET surface area and ICP-MS analysis. The mpg-CN/Pd nanocatalysts showed high activity in the Stille coupling reaction of a variety of electron-deficient and electron-rich aryl iodides/bromides and two different organostannanes with a wide substrate scope to afford the corresponding biaryls without using any bases and additional ligands under relatively mild conditions. The catalyst can be easily recovered from the reaction medium by centrifugation. It can be reused at least 5 times without any loss of activity.
- Cetin, Sultan,Kalay, Erbay,Kolemen, Safacan,Metin, ?nder
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p. 6714 - 6723
(2020/05/16)
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- Shuttling Catalyst: Facilitating C?C Bond Formation via Cross-Couplings with a Thermoresponsive Polymeric Ligand
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A poly(ethylene glycol) (PEG) linked ortho-MeO-phenyldicyclohexylphosphine (MeO-WePhos) ligand has been synthesized to promote Pd-catalyzed carbon-carbon bond formation by cross-couplings including Sonogashira, Heck, Hiyama and Stille reactions, providing corresponding (hetero)aryl substituted alkynes, alkenes and bi(hetero)aryls in good to excellent isolated yields with low Pd loadings. Facilitated by the lower critical solution temperature behaviour of the polymeric monophosphine ligand, the metal-complex could rapidly shuttle between organic and water phases as regulated by temperature, enabling highly efficient catalyst recycling via a simple phase separation. The chemical structure of ligand was determined by matrix-assisted laser desorption/ionization-time of flight mass spectrometry, nuclear magnetic resonance spectrometry and size-exclusion chromatography measurements. Notably, as demonstrated by the inductively coupled plasma-atomic emission spectrometry measurement, 98% Pd was kept in the water phase after 6 cycles of catalyst recycling experiments. Given the profound impact of transition-metal-catalyzed covalent bond formation and the increasing demand of sustainable chemistry, this work provides an alternative method to conduct cross-couplings with a polymeric shuttling catalyst.
- Wang, Erfei,Zhang, Jiawei,Zhong, Zhuoran,Chen, Kaixuan,Chen, Mao
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p. 419 - 423
(2020/01/08)
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- A novel magnetically recoverable palladium nanocatalyst containing organoselenium ligand for the synthesis of biaryls via Suzuki-Miyaura coupling reaction
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In the present work, a novel heterogeneous catalytic system involving palladium(II) complex as moisture- and air-stable organoselenium ligand supported on Fe3O4 nanoparticles modified by SiO2/azidopropyltriemethoxy silane was designed, synthesized and characterized using various physicochemical methods inclusive VSM, EDX, FE-SEM, TG, XRD, and FT-IR spectroscopy. The catalytic activity of the synthesized magnetic nanocatalyst which named Fe3O4@SiO2-T-Se/Pd(II) was evaluated in Suzuki-Miyaura coupling reactions for the preparation of corresponding biaryls using diverse aryl halides and arylboronic acids. The mild reaction conditions, variety of substrate scope, good yield, low reaction time, high stability, utilization of organoselenium compound as an air and moisture insensitive ligand and its immobilization on solid support, and more importantly effortless recovery and recyclability of the catalyst up to seven consecutive runs with no remarkable change in its activity are some of the interesting features of this protocol that makes it more beneficial from both industrial and environmental points of view.
- Rangraz, Yalda,Nemati, Firouzeh,Elhampour, Ali
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- Self-Assembling Supramolecular Hybrid Hydrogel Beads
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With the goal of imposing shape and structure on supramolecular gels, we combine a low-molecular-weight gelator (LMWG) with the polymer gelator (PG) calcium alginate in a hybrid hydrogel. By imposing thermal and temporal control of the orthogonal gelation methods, the system either forms an extended interpenetrating network or core–shell-structured gel beads—a rare example of a supramolecular gel formulated inside discrete gel spheres. The self-assembled LMWG retains its unique properties within the beads, such as remediating PdII and reducing it in situ to yield catalytically active Pd0 nanoparticles. A single PdNP-loaded gel bead can catalyse the Suzuki–Miyaura reaction, constituting a simple and easy-to-use reaction-dosing form. These uniquely shaped and structured LMWG-filled gel beads are a versatile platform technology with great potential in a range of applications.
- Piras, Carmen C.,Slavik, Petr,Smith, David K.
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supporting information
p. 853 - 859
(2019/12/24)
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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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- Cu(OAc)2 entrapped on ethylene glycol-modified melamine–formaldehyde polymer as an efficient heterogeneous catalyst for Suzuki–Miyaura coupling reactions
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This work is described as an environmental friendly approach for Cu(OAc)2 entrapped on ethylene glycol-modified melamine–formaldehyde-based polymeric material (Cu@MCOP) which has been successfully synthesized by simple approaches using commercially available starting materials via solvothermal techniques and without using any toxic reagents and chemicals. The structural, morphological, physicochemical characteristics and catalytic activity of the heterogeneous catalyst (Cu@MCOP) were analyzed by various instrumental methods including powder X-ray diffraction, FT-IR, UV-DRS, X-ray photoelectron spectroscopy, SEM and elemental mapping which have been used to authenticate the polymeric materials Cu@MCOP. The catalytic performance of Cu@MCOP as solid heterogeneous catalyst was evaluated in synthesis of various biphenyl derivatives through Suzuki–Miyaura cross-coupling reactions of various aryl halides with substituted organoboranes under normal reaction conditions. Furthermore, the copper catalyst was easily available, low cost, cheap and best instead of palladium, which shows good catalytic activity and excellent yield (up to 86%); the catalyst can be separated easily and recycled for more than five times. Graphic abstract: [Figure not available: see fulltext.].
- Sadhasivam, Velu,Sankar, Balakrishnan,Elamathi, Ganesan,Mariyappan, Mathappan,Siva, Ayyanar
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p. 681 - 700
(2019/11/03)
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- Palladium Supported on Silk Fibroin for Suzuki–Miyaura Cross-Coupling Reactions
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Silk fibroin supported Pd (Pd/SF) has been prepared and used as catalyst in Suzuki–Miyaura cross-coupling reactions in water/ethanol (4:1 v/v) mixture. The reactions proceed rapidly with aryl iodides and boronic acids with different electronic properties using low metal loading (0.38 mol-%). Pd/SF exhibits better recyclability compared to other biopolymer-supported Pd catalysts, up to nineteen cycles without loss of activity.
- Albano, Gianluigi,Farinola, Gianluca M.,Lo Presti, Marco,Milella, Antonella,Omenetto, Fiorenzo G.,Rizzo, Giorgio
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supporting information
p. 6992 - 6996
(2020/11/30)
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- Stille coupling method for catalyzing aromatic nitro compound by transition metal
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The invention provides a Stille coupling method for catalyzing aromatic nitro compound by transition metal. According to the method, in a nitrogen protection atmosphere, an aromatic nitro compound andan organic tin compound are used as substrates in an organic solvent, a cross coupling reaction is carried out under the action of an alkali under the action of a transition metal catalyst and a ligand, and the aromatic compound is obtained through a column chromatography or recrystallization method. The method is easy to operate, low in price, high in product conversion rate and good in substrate applicability; the method can be used for synthesizing a series of aromatic compounds, and the compounds have wide application values in the fields of pesticides, medicines, materials and the like.
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Paragraph 0025; 0028; 0049-0051
(2020/08/02)
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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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- 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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- 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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- Nickel-catalyzed and Li-mediated regiospecific C-H arylation of benzothiophenes
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A nickel-based catalytic system for the regiospecific C2-H arylation of benzothiophene has been established. NiCl2(bpy) is used as a catalyst in combination with LiHMDS as a base in dioxane. The catalytic system is applicable to a variety of functionalized benzothiophenes, as well as other heteroarenes including thiophene, benzodithiophene, benzofuran and selenophene in combination with iodo aryl electrophiles. The role of LiHMDS as a uniquely potent base and a postulated mechanism are discussed. The applicability of this system is finally demonstrated for the synthesis of an intermediate of an active pharmaceutical ingredient.
- Canivet, Jér?me,Grousset, Léonie,Hisler, Ga?lle,Mohr, Yorck,Quadrelli, Elsje Alessandra,Roux, Yoann,Wisser, Florian M.
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p. 3155 - 3161
(2020/06/19)
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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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- 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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- ORGANIC COMPOUND, PRODUCTION METHOD OF THE SAME, ORGANIC LIQUID CRYSTAL, ORGANIC SEMICONDUCTOR AND THE LIKE
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PROBLEM TO BE SOLVED: To provide an organic semiconductor showing high mobility and high thermal stability and having excellent solubility, an organic compound for the organic semiconductor, and a production method of the compound. SOLUTION: The present invention discloses an organic compound represented by the formula (1) and a production method of the compound, and applications of an organic semiconductor and the like using the organic compound. In the formula, Ar is an aromatic group selected from a phenyl or a thienyl which may have a substituent; one of R1 and R2 is a linear aliphatic group and the other is a hydrogen atom; and an acetylene bond in the parenthesis may be present or absent. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT
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Paragraph 0070; 0140-0141
(2020/07/25)
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- (N-Heterocyclic carbene) ion-pair palladium complexes: Suzuki–Miyaura cross-coupling studies in neat water under mild conditions
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The synthesis and characterization of a series of (N-heterocyclic carbene)PdCl3?(NMe3H)+ ion-pair complexes are presented. Applying the quaternary ammonium salt as the function with NHC–Pd(II) complexes yields the new ion-pair complexes. The NHC–Pd(II) ion-pair complexes work well by undergoing the Suzuki–Miyaura reaction with aryl chloride substrates in water under mild conditions in air at room temperature. Twenty products resulting from Suzuki–Miyaura coupling reactions carried out in the presence of the new NHC–Pd(II) ion-pair complex under mild optimal conditions were examined to determine the optimum yields.
- Chen, Ming-Tsz,Lin, Yu-Hsuan,Jian, Kun-Han
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- N,N′-bridged binuclear NHC palladium complexes: A combined experimental catalytic and computational study for the Suzuki reaction
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This work examines how N-donor bridged spacer ligands affect N-heterocyclic carbene (NHC) palladium complexes catalytic activities for Suzuki coupling reaction. Different degrees of structural flexibility binuclear NHC palladium complexes were synthesized. The more flexible nitrogen-based alkyl chain ligand shows similar performance with cycloamine counterparts in the Suzuki coupling reaction. Suzuki coupling examples were used in air and ambient temperature to reach moderate to completion yields in short time. Density functional theory calculations showed that the chelate effect, associated with a single Pd complex mechanism, plays a fundamental role in the pre-catalysis stage, supporting a reasonable of the kinetic activity observed experimentally.
- Chen, Ming-Tsz,Hsieh, Bing-Yan,Liu, Yi-Hung,Wu, Kuo-Hui,Lussari, Natália,Braga, Ataualpa A.C.
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- Transition-Metal-Free Synthesis of Heterobiaryls through 1,2-Migration of Boronate Complex
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The synthesis of a diverse range of heterobiaryls has been achieved by a transition-metal-free sp2–sp2 cross-coupling strategy using lithiated heterocycle, aryl or heteroaryl boronic ester and an electrophilic halogen source. The construction of heterobiaryls was carried out through electrophilic activation of the aryl–heteroaryl boronate complex, which triggered 1,2-migration from boron to the carbon atom. Subsequent oxidation of the intermediate boronic ester afforded heterobiaryls in good yield. A comprehensive 11B NMR study has been conducted to support the mechanism. The cross coupling between two nucleophilic cross coupling partners without transition metals reveals a reliable manifold to procure heterobiaryls in good yields. Various heterocycles like furan, thiophene, benzofuran, benzothiophene, and indole are well tolerated. Finally, we have successfully demonstrated the gram scale synthesis of the intermediates for an anticancer drug and OLED material using our methodology.
- Paul, Swagata,Das, Kanak Kanti,Manna, Samir,Panda, Santanu
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supporting information
p. 1922 - 1927
(2020/02/04)
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- Exploring the coordination confinement effect of divalent palladium/zero palladium doped polyaniline-networking: As an excellent-performance nanocomposite catalyst for C-C coupling reactions
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A pre-formed catalyst Pd2+/PANI composite for C-C coupling reaction was synthesized by combining the self-stabilized dispersion polymerization method with the in-situ composite material. Experiments have confirmed that the relatively high reduced structure (75%) in the polyaniline carrier is more favorable for the coupling reaction. Raman spectroscopy, solid nuclear magnetic, and X-ray photoelectron spectroscopy were performed to characterize the structures. The pre-formed catalyst has uniform coordination of divalent palladium and nitrogen in different valence states of the carrier polyaniline, which shows a good synergistic effect in the catalytic Ullmann reaction, and greatly reduces the use of reducing agents such as hydrazine hydrate. Compared with other studies, we analyzed the catalytic reaction mechanism in detail through real-time online infrared and XPS characterization. The results show that the divalent palladium in the catalyst and the zero-valent palladium generated by the in-situ reaction synergistically promote the reaction, while the polyaniline support acts as a stabilizer and dispersant, which prevents the agglomeration of the metal particles and prolongs increased catalyst life. The prepared Pd2+/PANI composites will become the most attractive alternative to traditional organic materials due to their wide applicability, high catalytic activity, stable recycling and relatively low price. This work provides a new theoretical basis for the understanding of the essential driving force of PANI catalytic activity and the cognition of the micro mechanism of action.
- Liang, Yanping,Liu, Wanyi,Song, Manrong,Sun, Yanyan,Wang, Gang,Wu, Zhiqiang,Zhan, Haijuan
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p. 177 - 188
(2020/03/17)
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- Air-Stable Fe3O4@SiO2-EDTA-Ni(0) as an Efficient Recyclable Magnetic Nanocatalyst for Effective Suzuki-Miyaura and Heck Cross-Coupling via Aryl Sulfamates and Carbamates
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The synthesis of inexpensive and novel air-stable Ni(0) nanoparticles immobilized on the EDTA-modified Fe3O4@SiO2 nanocatalyst was investigated in Suzuki-Miyaura and Heck cross-coupling reactions. This catalytic system displayed a greatly improved substrate scope for the carbon–carbon bond formations starting from a wide range of green and economical electrophiles aryl and heteroaryl carbamates and sulfamates via highly efficient method under mild, operationally simple reaction conditions. The synthesized heterogeneous catalyst was also fully characterized by FT-IR, TEM, XRD, DLS, FE-SEM, UV–Vis, EDX, XPS, TGA, NMR, VSM, ICP and elemental analysis techniques. The heterogeneous magnetic nanocatalyst can easily be recovered by an external magnetic field and reused for the next reactions for at least seven times with negligible leaching of catalyst and no substantial decrement in the activity. All these highlights have made the present protocol an interesting, simple and environmentally benign process with low catalyst loading and easy manipulations.
- Dindarloo Inaloo, Iman,Majnooni, Sahar,Eslahi, Hassan,Esmaeilpour, Mohsen
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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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- 1-Aryltriazenes in the Suzuki, Heck, and Sonogashira Reactions in Imidazolium-ILs, with [BMIM(SO3H)][OTf] or Sc(OTf)3 as Promoter, and Pd(OAc)2 or NiCl2·glyme as Catalyst
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1-Aryltriazenes, the protected and more stable form of aryl-diazonium species, can be conveniently unmasked with Br?nsted acidic-IL or Sc(OTf)3 and coupled with a host of aryl/heteroaryl boronic acids, styrenes, and aryl/alkyl acetylenes in the Suzuki, Heck and Sonogashira reactions in one-pot and in respectable isolated yields, by using palladium or nickel catalyst in readily available imidazolium ILs as solvent, under mild conditions. The scope of these reactions are explored, and the potential for recovery/reuse of the IL solvent is also addressed.
- Sutar, Suraj M.,Savanur, Hemantkumar M.,Malunavar, Shruti S.,Prabhala, Pavankumar,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
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supporting information
p. 6088 - 6093
(2019/09/17)
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- Palladium nanoparticles-decorated triethanolammonium chloride ionic liquid-modified TiO2 nanoparticles (TiO2/IL-Pd): A highly active and recoverable catalyst for Suzuki–Miyaura cross-coupling reaction in aqueous medium
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In this work, an easily obtained procedure was successfully implemented to prepare novel palladium nanoparticles decorated on triethanolammonium chloride ionic liquid-functionalized TiO2 nanoparticles [TiO2/IL-Pd]. Different methods were carried out for characterizations of the synthesized nanocatalyst (HR-TEM, XPS, XRD, FE-SEM, EDX, FT-IR and ICP). TiO2/IL-Pd indicated good catalytic activity for the Suzuki–Miyaura cross-coupling reaction of arylboronic acid with different aryl halides in aqueous media at ambient temperature. The recycled catalyst was investigated with ICP to amount of Pd leaching after 6 times that had diminished slightly, Thus, was confirmed that the nanocatalyst has a good sustainability for C–C Suzuki–Miyaura coupling reaction. The catalyst can be conveniently separated by filtration of the reaction mixture and reused for 6 times without significant loss of its activity. It supplies an environmentally benign alternative path to the existing protocols for the Suzuki–Miyaura reaction.
- Veisi, Hojat,Kamangar, Sheida Ahany,Mohammadi, Pourya,Hemmati, Saba
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- Bioinspired Palladium Nanoparticles Supported on Soil-Derived Humic Acid Coated Iron-Oxide Nanoparticles as Catalyst for C–C Cross-Coupling and Reduction Reactions
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Abstract: Pd nanoparticles supported on humic acid-coated nanoferrites as magnetically-recoverable catalyst was expediently prepared from inexpensive precursors and characterized by techniques such as SEM, TEM, XPS, FT-IR, XRD, ICP-AES, EDX. The as made catalyst displayed an admirable catalytic activity towards the Suzuki–Miyaura cross-coupling reaction of aryl halides (or) aryl diazonium salts with aryl boronic acid in non-toxic solvent EtOH/water under mild conditions. The same catalyst showed high efficiency for the Heck reaction of aryl halides with styrene was carried out with high efficiency offering good yields under ligand-free conditions. Additionally, the reduction of olefins using molecular hydrogen was also achieved using the same catalyst under ambient and base-free conditions affording the products in good to excellent yields. The magnetic activity of nano-Fe3O4 allowed the effortless recovery of the catalyst and demonstrated subsequent recyclability up to 5 cycles without a significant loss in the activity. Graphical Abstract: [Figure not available: see fulltext.].
- Chinchole, Anurag N.,Dubey, Abhishek V.,Kumar, A. Vijay
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p. 1224 - 1236
(2019/02/26)
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- Palladium(ii) complexes supported by PBP and POCOP pincer ligands: A comparison of their structure, properties and catalytic activity
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A Pd(ii) chloride complex supported by a Yamashita-Nozaki PBP pincer ligand, [C6H4-1,2-(NCH2PtBu2)2B]PdCl (1a), was synthesized. The structure, properties and catalytic activity of complex 1a were compared with those of the corresponding POCOP pincer complex [C6H3-2,6-(OPtBu2)2]PdCl (2a). It was found that the Pd centre in complex 1a is more electron rich and easier to be oxidized than that in complex 2a; complex 1a is a much better catalyst for Suzuki-Miyaura cross-coupling reactions than complex 2a. Starting from complexes 1a and 2a, two series of Pd(ii) pincer complexes bearing a SH, BH4, NCS, NCSe or N3 covalent ligand, [C6H4-1,2-(NCH2PtBu2)2B]PdY (Y = SH, 1b; BH4; 1c; NCS, 1d; NCSe, 1e; and N3, 1f) and [C6H3-2,6-(OPtBu2)2]PdY (Y = SH, 2b; BH4, 2c; NCS, 2d; NCSe, 2e; and N3, 2f), were synthesized and fully characterized. Single crystal X-ray diffraction analysis indicated that the Pd centre is less tightly chelated in PBP pincer complexes. The strong σ-donor ability of the PBP pincer ligand has little influence on the structure of the covalent ligand possessing both σ-donor and π-Acceptor properties. However, the stretching vibrational frequencies of NCS, NCSe and N3 ligands and the coordination mode of the BH4 ligand are significantly different in these two types of palladium pincer complexes.
- Ding, Yazhou,Ma, Qiang-Qiang,Kang, Jiaxin,Zhang, Jie,Li, Shujun,Chen, Xuenian
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p. 17633 - 17643
(2019/12/23)
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- Band Gap Modification of TiO2 Nanoparticles by Ascorbic Acid-Stabilized Pd Nanoparticles for Photocatalytic Suzuki–Miyaura and Ullmann Coupling Reactions
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In this study, synthesis, characterization and photocatalytic performance of surface-modified TiO2 nanoparticles with ascorbic acid-stabilized Pd nanoparticles are presented. The structure, composition and morphology of as-prepared nanophotocatalyst were characterized by UV-DRS, FT-IR, ICP-AES, TEM and XPS analysis. Ascorbic acid-stabilized Pd nanoparticles induced visible light driven photocatalytic property on the surface of TiO2 which are otherwise insensitive to visible light owing to the wide band gap. The catalytic system worked well for the Suzuki–Miyaura cross-coupling and Ullmann homocoupling under compact fluorescent light as a visible source with significant activity, selectivity and recyclability. Good to excellent yields of biaryl products were obtained for various aryl halides having different electronic demands and even aryl chlorides. Our results proposed that the improved photoactivity predominantly benefits from the synergistic effects of ascorbic acid-stabilized Pd nanoparticles on TiO2 nanoparticles that cause efficient separation and photoexcited charge carriers and photoredox capability of nanocatalyst. Thus, tuning of band gap of TiO2 making a visible light sensitive photocatalyst, demonstrates a significant advancement in the photocatalytic Suzuki–Miyaura and Ullmann coupling reactions. Graphical Abstract: [Figure not available: see fulltext.].
- Feizpour, Fahimeh,Jafarpour, Maasoumeh,Rezaeifard, Abdolreza
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