- Selective Synthesis of Substituted Pyridines and Pyrimidines through Cascade Annulation of Isopropene Derivatives
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Diverse substituted pyridines and pyrimidines with high selectivity were obtained using a concise and efficient protocol developed herein. The reaction proceeds via metal-free cascade annulation of isopropene derivatives. Using isopropene derivatives as C3 synthons, NH4I as the “N” source, and formaldehyde or dimethyl sulfoxide as the carbon source, this reaction realizes the efficient formation of intermolecular C-N and C-C bonds.
- Chen, Lu,He, Runfa,Huang, Yubing,Li, Jiaming,Li, Jian,Li, Yibiao,Liu, Jiasheng,Liu, Yang
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supporting information
p. 1620 - 1625
(2022/03/14)
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- An unsymmetrical Schiff-base derived recyclable Pd-catalyst for Suzuki–Miyaura and Sonogashira reactions in aqueous media
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Abstract: A water-soluble palladium (II) complex containing an unsymmetrical Schiff-base ligand was synthesized and applied as catalyst Suzuki–Miyaura and Sonogashira cross-coupling reactions in aqueous media. Notably, moderate to excellent yields of biaryls were obtained in Suzuki reaction with usually less reactive aryl and heteroaryl chlorides under relatively mild condition. Moderate-to-high yields of aryl-alkynes were also obtained in Sonogashira reactions using aryl bromides. Apart from hydrophilic nature, the accomplishment of reactions in water, high recyclability, broad functional group tolerance, etc., are other advantages of the system. Graphic abstract: [Figure not available: see fulltext.]
- Das, Pankaj,Gogoi, Achinta,Puzari, Amlan
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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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- 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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- 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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- 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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- 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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- A new approach to large scale production of dimethyl sulfone: A promising and strong recyclable solvent for ligand-free Cu-catalyzed C-C cross-coupling reactions
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Dimethyl sulfone (DMSN) was easily prepared through efficient oxidation of dimethyl sulfoxide (DMSO) and used as a strong and green solvent for organic reactions. A mixture of HNO3/NaOCl was used as an oxidizing agent for efficient oxidation of DMSO to DMSN. The effect of DMSN was evaluated for copper-catalyzed coupling reactions. It is worth noting that DMSN could play the role of a ligand for copper ions. A general survey was accomplished for various types of C-C cross-coupling reactions catalyzed by CuI in DMSN in the absence of any ligand. Moderate to good yields were achieved for Sonogashira, Heck, and Suzuki cross-coupling reactions. Finally, DMSN was recovered and reused for several consecutive runs without any loss of its activity.
- Cheng, Shen,Wei, Wei,Zhang, Xingyu,Yu, Hewei,Huang, Mingming,Kazemnejadi, Milad
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p. 2069 - 2076
(2020/04/07)
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- Synthesis of heterobiaryls via Suzuki-Miyaura coupling reaction of potassium aryltrifluoroborates with heteroaryl halides in aqueous systems
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A variety of heterobiaryl compounds have been synthesized by the Suzuki-Miyaura coupling reactions of heteroaryl halides with potassium aryltrifluoroborates. Pd (OAc)2 was found to be highly efficient for the Suzuki-Miyaura coupling reactions of various heteroaryl halides with potassium aryltrifluoroborates in aqueous systems, delivering the corresponding heterobiaryl compounds in good to excellent yields.
- Liu, Leifang,Zhao, Kai,Li, Wenbo,Liu, Mingli,Chen, Yuting,Dong, Yan
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- A Monophosphine Ligand Derived from Anthracene Photodimer: Synthetic Applications for Palladium-Catalyzed Coupling Reactions
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Herein, we present an air-stable dianthracenyl monophosphine ligand (diAnthPhos) which can be prepared in two steps from commercially available anthracene derivatives. The ligand exhibits excellent efficiency for palladium-catalyzed coupling reactions. In particular, Miyaura borylation of heterocycle-containing electrophiles can be facilitated employing the diAnthPhos ligand with a broad substrate scope and low catalyst loading. The valuable synthetic utility of the new ligand is further demonstrated by a one-pot Miyaura borylation/Suzuki coupling protocol for heteroaryl-containing substrates.
- Wang, Xin,Liu, Wei-Gang,Tung, Chen-Ho,Wu, Li-Zhu,Cong, Huan
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supporting information
p. 8158 - 8163
(2019/09/07)
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- Palladium(ii) ligated with a selenated (Se, CNHC, N-)-type pincer ligand: An efficient catalyst for Mizoroki-Heck and Suzuki-Miyaura coupling in water
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A new 1-[N-benzylacetamido]-3-[1-(2-phenylselenylethyl)]benzimidazolium chloride (L), the precursor of a novel (Se, CNHC, N-)-type pincer ligand (L) was synthesised in high yield through a sequence of consecutive reactions of 1H-benzimidazole with ethylene dichloride, sodium selenophenolate, and N-benzyl-2-chloroacetamide. The palladium-promoted reaction of L with PdCl2 resulted in a moisture- and air-insensitive complex [Pd(L-H2Cl)Cl] (1), which demonstrated outstanding catalytic potential for Mizoroki-Heck coupling of aromatic bromides and chlorides (with yields up to 94% and 70%, respectively) at very low catalyst loading (0.2 mol%) and under mild reaction conditions in water. The complex (1) was also investigated for Suzuki-Miyaura coupling and found to be selectively efficient (yields up to 94%) for Suzuki-Miyaura coupling of aromatic bromides at 0.01 mol% of 1 in water. All coupling reactions were carried out in the green and economical solvent, water, which is highly desirable for bulk synthesis of complex molecules in industry. During the catalytic process, complex 1 converted into PdSe nanoparticles (NPs, size range 5-6 nm) in situ. The morphology and composition of these NPs were analysed through high-resolution transmission electron microscopy and transmission electron microscopy-energy dispersive X-ray spectroscopy, respectively. The core-level, X-ray photoelectron spectroscopy analysis confirmed the presence of stable Pd0 and Pd2+ oxidation states in these PdSe NPs. Based on further experimental investigations, these nanoparticles were found to work as a stock of true catalytic species. The hot filtration test, as well as the two-phase test, confirmed the largely homogeneous nature of the catalytic process, which probably proceeds by leaching of solution-phase Pd species from these NPs.
- Sharma, Kamal Nayan,Satrawala, Naveen,Srivastava, Avinash Kumar,Ali, Munsaf,Joshi, Raj Kumar
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p. 8969 - 8976
(2019/10/28)
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- Desulfinative and denitrogenative palladium-catalyzed cross-coupling of arylsulfonyl hydrazides with aryl diazonium salts
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Palladium-catalyzed cross-coupling of arylsulfonyl hydrazides with aryl diazonium salts to provide biaryl products under relatively mild conditions is established. This reaction proceeded smoothly with tetrabutylammonium iodide and gave the corresponding
- Shang, Yonghui
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- Magnesium oxide supported bimetallic Pd/Cu nanoparticles as an efficient catalyst for Sonogashira reaction
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PdCu bimetallic nanoparticles with a diameter of about 3 nm are prepared and supported on a polymeric vinylimidazole ligand modified magnesium oxide. This new material is characterized using different analysis such as XRD, XPS, CHNS, TEM, SEM, and EDX-mapping. PdCu supported on MgO (MgO@PdCu) exhibits high catalytic activity in the Sonogashira coupling reaction of aryl iodides, bromides and chlorides with low Pd loading (0.05-0.2 mol%). This catalyst is recovered and recycled for 11 consecutive runs preserving its catalytic activity in the model reaction of iodobenzene with phenylacetylene for at least 8 cycles. Reused catalyst is characterized with TEM, XPS and EDX showing preservation of the catalyst structure. Using hot filtration and PVP poisoning tests, the catalyst shows a heterogeneous behavior for the model reaction.
- Gholinejad, Mohammad,Bahrami, Maedeh,Nájera, Carmen,Pullithadathil, Biji
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- Method for preparing bi-arene from aryl diazo salts and aryl sulfonylhydrazide
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The invention discloses a method for preparing bi-arene from aryl diazo salts and aryl sulfonylhydrazide. The method comprises the following steps of performing denitrification coupling reaction on aryl diazo salts and aryl sulfonylhydrazide in an organic solvent under the effects of palladium catalysts, ligands and additives; after the reaction is completed, performing post-treatment to obtain the bi-arene. The method provided by the invention has the advantages that the substrate price is low; the property is stable; the operation is convenient; meanwhile, the reaction yield is high; the substrate general applicability is high.
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Paragraph 0044; 0045; 0046
(2018/10/19)
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- Pd/REOs catalysts applied to the Suzuki-Miyaura coupling. A comparison of their catalytic performance and reusability
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Two new palladium catalysts based on rare earth oxide supports, namely, Pd/Dy2O3 and Pd/Yb2O3 were prepared by the incipient wetness impregnation method, followed by calcination at 600 °C. Both compounds, which were fully characterized, were tested as catalysts in the Suzuki-Miyaura reaction and their catalytic activity was compared with that of already known Pd/La2O3, Pd/CeO2, Pd/Pr6O11, Pd/Sm2O3, and Pd/Gd2O3. It has been found that the nature of the support strongly affects the catalytic activity. The scope of the catalytic protocol was investigated and quantitative yields of the coupling products (21 examples are reported) were always observed using a low metal amount (0.05 mol%). A systematic investigation on the reusability of the entire set of catalytic systems has been carried out. All catalysts showed to be successfully recyclable, and also in this case the nature of the rare earth element is crucial. The highest reusability was observed for catalysts Pd/CeO2 and Pd/Sm2O3.
- Del Zotto, Alessandro,Colussi, Sara,Trovarelli, Alessandro
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p. 275 - 283
(2017/09/30)
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- Preparation and Reactivation of Heterogeneous Palladium Catalysts and Applications in Sonogashira, Suzuki, and Heck Reactions in Aqueous Media
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A new type of heterogeneous palladium catalyst, PdMgAl-LDH, was facilely prepared by the immobilization of Pd2+ species in the layers of a Mg-Al layered double hydroxide (LDH) with co-precipitation, and then fully characterized by using powder XRD, thermogravimetric differential thermal analysis, TEM, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy techniques. These catalysts can efficiently catalyze copper-free Sonogashira, Suzuki and Heck coupling reactions of various aryl iodides, bromides, and chlorides in aqueous media under phosphine-ligand- and organic-base-free conditions. These catalysts feature easy recovery through simple filtration and could be reused at least six times without a marked loss in activity. Notably, they can be facilely reactivated by a combination of nitrolysis with co-precipitation. The basic LDH skeletons could effectively stabilize the Pd0 species created in situ and donate electron density to the Pd0 center to facilitate the oxidative addition of aryl halides, thus the PdMgAl-LDH catalysts are stable during catalysis.
- Zhang, Sheng-Yan,Yu, Kai,Guo, Yu-Shuang,Mou, Rui-Qi,Lu, Xiao-Fan,Guo, Dian-Shun
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p. 803 - 813
(2018/10/31)
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- Thioether–NHC-Ligated PdII Complex for Crafting a Filtration-Free Magnetically Retrievable Catalyst for Suzuki–Miyaura Coupling in Water
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A new benzimidazolium salt, 1-[benzylaminocarbonylmethyl]-3-(2-phenylsulfanylethyl)-1H-benzimidazolium chloride (L), which is a precursor of a novel thioether-functionalized NHC, has been synthesized by subjecting 1H-benzimidazole to a sequence of reactions with 1,2-dichloroethane, sodium thiophenolate, and N-benzyl-2-chloroacetamide, successively. The moisture/air-insensitive complex [Pd(L–HCl)Cl2] (1) was prepared by the reaction of L with PdCl2. The molecular structure of 1, established by X-ray crystallography, revealed a square-planar geometry around Pd. Complex 1 was screened for Suzuki–Miyaura coupling reactions of various aryl/heteroaryl bromides (yields of up to 94 % in 2 h) in water at room temperature. Furthermore, complex 1 was immobilized onto the surface of aminopropyl-functionalized silica-coated magnetite nanoparticles [NPs, Fe3O4@SiO2-(CH2)3-NH2] by a stepwise modification strategy to develop the heterogeneous magnetically retrievable catalyst Fe3O4@SiO2-1′, in which the amide functionality present in the side-arm of the NHC within the NHC–PdII complex serves as linker. This magnetic nanosupport, bearing palladium complexes incorporating a novel thioether-based NHC ligand that functions in aqueous aerobic medium and can be easily separated, renders Fe3O4@SiO2-1′ a most desirable catalyst for the Suzuki–Miyaura coupling reaction. It was also observed that the catalyst was effective for up to seven cycles and was easily separated from the reaction medium by the use of an external magnet, further increasing its appeal.
- Nayan Sharma, Kamal,Satrawala, Naveen,Kumar Joshi, Raj
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p. 1743 - 1751
(2018/05/14)
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- Nitro group reduction and Suzuki reaction catalysed by palladium supported on magnetic nanoparticles modified with carbon quantum dots generated from glycerol and urea
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Glycerol and urea were used as green and cheap sources of carbon quantum dots (CQD) for modifying Fe3O4 nanoparticles (NPs). The obtained CQD@Fe3O4 NPs were used for the stabilization of palladium species and the prepared catalyst, Pd@CQD@Fe3O4, was characterized using various techniques. This magnetic supported palladium was applied as an efficient catalyst for the reduction of aromatic nitro compounds to primary amines at room temperature using very low palladium loading (0.008?mol%) and also for the Suzuki–Miyaura cross-coupling reaction of aryl halides as well as challenging heteroaryl bromides and aryl diazonium salts with arylboronic acids and with potassium phenyltrifluoroborate. This magnetically recyclable catalyst was recovered and reused for seven consecutive runs in the reduction of 4-nitrotoluene to p-toluidine and for ten consecutive runs in the reaction of 4-iodoanisole with phenylboronic acid with small decrease of activity. The catalyst reused in the Suzuki reaction was characterized using transmission electron microscopy, vibrating sample magnetometry and X-ray photoelectron spectroscopy. Using experiments such as hot filtration and poisoning tests, it has been shown that the true catalyst works under homogeneous conditions according to the release–return pathway of active palladium species.
- Gholinejad, Mohammad,Zareh, Fatemeh,Nájera, Carmen
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- Palladium complexes with two unsymmetrical Schiff base ligands: Highly active catalyst for activation of chloroarenes in Suzuki-Miyaura reaction
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Two new unsymmetrical Schiff base derived palladium(II) complexes, [PdCl2{bis(salicylidene)-2-aminobenzamide}] (C1) and [PdCl2{N,N'-bis(salicylidene)-2-aminobenzylamine}] (C2) have been synthesized and characterized. The complexes have been explored as catalysts for the Suzuki-Miyaura cross-coupling reactions of aryl halides with arylboronic acids. An optimization study reveals that under similar experimental conditions, the complex C1 shows superior activity over the complex C2. Using the complex C1 as catalyst, less reactive chloroarenes are efficiently converted to their corresponding biaryls under relatively mild conditions (80oC, 0.5 mol% catalyst) using EtOH as an environmentally safer reaction media. Excellent yields of cross coupling products are also obtained with aryl bromides at room temperature in neat water with low catalyst loading (0.02 mol %).
- Puzari, Amlan,Shahnaz, Nasifa,Das, Pankaj
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p. 837 - 842
(2020/06/26)
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- Selective aryl radical transfers into N-heteroaromatics from diaryliodonoium salts with trimethoxybenzene auxiliary
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We have found that a series of trimethoxybenzene-based diaryliodonium(III) salts I (ArI+Ar’X-, where Ar = various aryl groups, Ar’ = 2,4,6-trimethoxyphenyl, X- = counterion) can exclusively cause Ar-transfers during the base-induced radical couplings with N-heteroaromatic compounds 1 by working the trimethoxybenzene ring (Ar’) as an inert coupling auxiliary. By the treatment with N-heteroaromatics 1 as the solvent, the metal-free arylations utilizing the specific salts I initiated by solid NaOH upon heating selectively produced the corresponding biaryls 2 in good yields without the formation of the trimethoxybenzene (Ar’) coupling product.
- Dohi, Toshifumi,Ueda, Shohei,Hirai, Akiko,Kojima, Yusuke,Morimoto, Koji,Kita, Yasuyuki
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p. 1272 - 1284
(2019/11/14)
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- Cobalt-Catalyzed Cross-Coupling Reactions of Arylboronic Esters and Aryl Halides
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An efficient cobalt catalyst system for the Suzuki-Miyaura cross-coupling reaction of arylboronic esters and aryl halides has been identified. In the presence of cobalt(II)/terpyridine catalyst and potassium methoxide, a diverse array of (hetero)biaryls have been prepared in moderate to excellent yields.
- Duong, Hung A.,Wu, Wenqin,Teo, Yu-Yuan
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supporting information
p. 4363 - 4366
(2017/12/05)
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- Insight into Copper Catalysis: In Situ Formed Nano Cu2O in Suzuki-Miyaura Cross-Coupling of Aryl/Indolyl Boronates
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A ligand-free copper catalyzed Suzuki-Miyaura coupling of 3,5-diiodopyridine with aryl and indole boronates has been explored in good to excellent yields. In situ generation of nano-Cu2O from CuCl2 under the reaction conditions has been discovered for the first time. The generality of the reaction was further demonstrated by the arylation of 5-iodopyrimidine, iodopyridines, iodobenzenes, and diiodobenzenes and resulted in good to moderate yields. Moreover, bisindole alkaloid Scalaridine A has been successfully synthesized in 60% overall yield.
- Ranjani, Ganapathy,Nagarajan, Rajagopal
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p. 3974 - 3977
(2017/08/14)
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- Synthesis of zwitterionic palladium complexes and their application as catalysts in cross-coupling reactions of aryl, heteroaryl and benzyl bromides with organoboron reagents in neat water
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N-(3-Chloro-2-quinoxalinyl)-N′-arylimidazolium salts (aryl = 2,6-diisopropylphenyl [HL1Cl]Cl, aryl = mesityl [HL2Cl]Cl) have been synthesized by treating 2,3-dichloroquinoxaline with the corresponding N′-arylimidazole in neat water. Facile reactions of these imidazolium salts with Pd(PPh3)4 and Pd2(dba)3/PPh3 (dba = dibenzyledene acetone) at 50 °C have afforded zwitterionic palladium(ii) complexes [Pd(HL1)(PPh3)Cl2] (I) and [Pd(HL2)(PPh3)Cl2] (II) in excellent yields. I and II have been tested for their ability to catalyze Suzuki-Miyaura cross coupling (SMC) reactions in neat water/K2CO3 and are found to be highly active for carrying out these reactions between aryl bromides and organoboron reagents. Furthermore, the scope of the catalyst I was also examined by employing (hetero)aryl bromides, hydrophilic aryl bromides, benzyl bromides and various organoboron reagents. More than 80 aryl/benzyl bromide-arylboronic acid combinations were screened in neat water/K2CO3 and it was found that I was a versatile catalyst, which produced biaryls/diarylmethanes in excellent yields. A TON of 82 000 was achieved by using I. Studies on the mechanism have also been carried out to investigate the involvement of carbene complexes in the catalytic path. Poison tests and a two-phase test were also conducted and the results are reported.
- Ramakrishna,Dastagiri Reddy
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p. 8598 - 8610
(2017/07/12)
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- Palladium Stabilized by Amino-Vinyl Silica Functionalized Magnetic Carbon Nanotube: Application in Suzuki–Miyaura and Heck–Mizoroki Coupling Reactions
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Abstract: This study describes an investigation on Suzuki and Heck cross-couplings of aryl electrophiles in the presence of heterogeneous Pd nanoparticles supported on amino-vinyl silica functionalized magnetic carbon nanotube. The core–shell contains CNT@Fe3O4@SiO2-Pd in which the functionalized SiO2 helps the stabilization of Pd nanoparticles and also responsible for the reduction of Pd(II) to Pd(0) without the need for adding external reducing agents. All of the reactions were done under phosphine-free condition. Graphical Abstract: [Figure not available: see fulltext.]
- Khalili, Dariush,Banazadeh, Ali Reza,Etemadi-Davan, Elham
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p. 2674 - 2687
(2017/09/06)
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- Biogenic synthesis of palladium nanoparticles and their applications as catalyst and antimicrobial agent
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This paper describes a simple in-situ process of synthesizing highly dispersed palladium nanoparticles (PdNPs) using aqueous leaf extract of GarciniapedunculataRoxb as bio-reductant and starch (0.3%) as bio-stabilizer. The PdNPs are characterized by techniques like FTIR, TEM, SEM-EDX, XRD and XPS analysis. It is worthnoting thatwhen the synthesis of nanoparticles was carried out in absence of starch, agglomeration of particles has been noticed.The starch-assisted PdNPs showed excellent aqueous-phase catalytic activities for three important reactions: the Suzuki-Miyaura cross-coupling reactions of aryl halides (aryl bromides and iodides) with arylboronic acids; selective oxidations of alcohols to corresponding carbonyl compounds; and reduction of toxic Cr(VI) to nontoxic Cr(III). Our catalyst could be reused up to four cycles without much compromising with its activity. Furthermore, the material also demonstrated excellent antimicrobial and anti-biofilm activities against a novel multidrug resistant clinical bacterial isolate Cronobactersakazakii strain AMD04. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of PdNPswere found to be 0.06 and 0.12 mM respectively.
- Hazarika, Munmi,Borah, Debajit,Bora, Popymita,Silva, Ana R.,Das, Pankaj
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- An N-Heterocyclic Carbene-Nickel Half-Sandwich Complex as a Precatalyst for Suzuki-Miyaura Coupling of Aryl/Heteroaryl Halides with Aryl/Heteroarylboronic Acids
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A nickel half-sandwich complex supported by our original NHC ligand was developed as a robust precatalyst for Suzuki-Miyaura cross-coupling. The addition of PPh3 was a crucial element in the suppression of side reactions and in accelerating the cross-coupling reaction. By employing the optimal conditions, aryl-aryl, heteroaryl-aryl, and heteroaryl-heteroaryl couplings were achieved.
- Ando, Shin,Matsunaga, Hirofumi,Ishizuka, Tadao
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p. 1266 - 1272
(2018/06/18)
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- Green synthesis of carbon quantum dots from vanillin for modification of magnetite nanoparticles and formation of palladium nanoparticles: Efficient catalyst for Suzuki reaction
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In this report we prepared carbon quantum dots (CQD) from vanillin as an ecofriendly and naturally abundant compound for modification of magnetic nanoparticles (CQD@Fe3O4 NPs). This new magnetic solid has been used for complete reduction of PdCl2 with formation of stabilized palladium nanoparticles (Pd@CQD@Fe3O4 NPs) and characterized by SEM, TEM, EDX, solid UV, VSM, XPS, XRD, and N2 adsorption–desorption analyses. These magnetic supported Pd NPs have been used as an efficient catalyst for the Suzuki-Miyaura cross-coupling reactions of aryl bromides at room temperature in aqueous ethanol and of aryl chlorides at 120 °C in PEG200 under low catalyst loading in air. The heterogeneous catalyst can be easily recovered by an external magnet and reused for eight consecutive runs.
- Gholinejad, Mohammad,Najera, Carmen,Hamed, Fatemeh,Seyedhamzeh, Mohammad,Bahrami, Maede,Kompany-Zareh, Mohsen
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p. 5585 - 5592
(2017/08/26)
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- Oxygen-promoted Pd/C-catalyzed Suzuki-Miyaura reaction of potassium aryltrifluoroborates
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A simple and highly efficient protocol has been developed for the Pd/C-catalyzed ligand-free Suzuki-Miyaura reaction of potassium aryltrifluoroborates. In this catalytic system, the results demonstrate that oxygen plays a positive role in the cross-coupling reaction. In addition, this catalytic system could be successfully applied to synthesize biaryl compounds containing a carbazole moiety and the catalyst was recycled seven times without significant loss of catalytic activity.
- Liu, Chun,Liu, Chao,Li, Xin-Min,Gao, Zhan-Ming,Jin, Zi-Lin
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p. 631 - 634
(2016/05/19)
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- Pd-Catalyzed Ligand-Free Synthesis of Arylated Heteroaromatics by Coupling of N-Heteroaromatic Bromides with Iodobenzene Diacetate, Iodosobenzene, or Diphenyliodonium Salts
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An efficient method for synthesizing arylated heteroaromatics has been reported via Pd-catalyzed ligand-free cross-coupling of N-heteroaromatic bromides with iodine(III) reagents under mild conditions. Iodobenzene diacetate, iodosobenzene, and diphenyliod
- Wang, Xiajun,He, Yongqin,Ren, Mengdan,Liu, Shengkang,Liu, He,Huang, Guosheng
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p. 7958 - 7962
(2016/09/09)
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- Metal-free arylation of pyrimidines through a photochemical process
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Pyrimidinyl and pyrazinyl radicals were generated under moderate energetic irradiation conditions (UVA), and proved to be prompt to undergo C-C bond formation processes. Hetero-biaryl derivatives were obtained in good to high yields with highly interesting functional group selectivities. Bis hetero-biaryls were also easily accessible leading to original compounds, ready for further transformations. Experiments supporting radical processes have been reported.
- Ruch, Jonas,Aubin, Ariane,Erbland, Guillaume,Fortunato, Audrey,Goddard, Jean-Philippe
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supporting information
p. 2326 - 2329
(2016/02/18)
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- Iron oxide nanoparticles modified with carbon quantum nanodots for the stabilization of palladium nanoparticles: An efficient catalyst for the Suzuki reaction in aqueous media under mild conditions
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Magnetic Fe3O4 nanoparticles (NPs) functionalized with carbon dots (C-dots) that contain carboxylic acid and hydroxyl groups were synthesized successfully and used for the reduction of PdII and the formation of Pd NPs. The new material was characterized by SEM, TEM, energy-dispersive spectroscopy, solid UV spectroscopy, vibrating sample magnetometry, XRD, and X-ray photoelectron spectroscopy and was used as a very efficient catalyst in the Suzuki-Miyaura cross-coupling reaction of aryl bromides and chlorides with arylboronic acids in aqueous media. Design of experiments indicates that the use of 0.22 mol % of Pd, K2CO3 as the base, and aqueous ethanol are the best reaction conditions. The reactions of aryl bromides take place at room temperature, and aryl chlorides react at 80 °C. The easily synthesized and air-stable catalyst Pd@C-dots@Fe3O4 NPs could be separated from the reaction mixture by using an external magnet and reused in eight consecutive runs with no significant loss of catalytic activity. Dot to dot: Pd supported on Fe3O4 nanoparticles modified with carbon quantum nanodots is shown to be an efficient catalyst for Suzuki coupling reactions.
- Gholinejad, Mohammad,Seyedhamzeh, Mohammad,Razeghi, Mehran,Najera, Carmen,Kompany-Zareh, Mohsen
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p. 441 - 447
(2016/02/05)
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- Palladium supported on phosphinite functionalized Fe3O4 nanoparticles as a new magnetically separable catalyst for Suzuki-Miyaura coupling reactions in aqueous media
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Novel phosphinite functionalized magnetic (Fe3O4) nanoparticles having silica nanoshells containing an imidazolium ionic liquid moiety have been successfully synthesized and used as a support and stabilizer for palladium nanoparticles. The obtained compound was characterized by SEM, TEM, EDX, solid UV, VSM, XRD, XPS, FT-IR, and N2 adsorption-desorption analyses. This magnetic composite has been applied as the catalyst in the Suzuki-Miyaura coupling reaction of aryl halides (I, Br, Cl) with arylboronic acids in aqueous media under mild reaction conditions and low palladium loading. The air stable catalyst could be easily separated from the reaction mixture using an external magnet and reused eight consecutive times with small drops in its catalytic activity.
- Gholinejad, Mohammad,Razeghi, Mehran,Ghaderi, Arash,Biji, Pullithadathil
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p. 3117 - 3127
(2016/05/24)
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- Carboxyamido/carbene ligated palladium (II) complex: A versatile catalyst for the synthesis of aryl-substituted heteroarenes
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Carboxy amido/carbene ligated Pd-complex catalyzed Suzuki-Miyaura cross-coupling of aryl-boronic acids with heteroaryl bromides is described. The protocol has a broad substrate scope that includes electron-rich, electron-deficient and sterically hindered arylboronic acids and heteroaryl bromides. The catalytic activity of the catalyst has been further investigated in the coupling of 2,6-dibromopyridine with arylboronic acids.
- Vishnuvardhan Reddy, Police,Parsharamulu, Thupakula,Annapurna, Manne,Likhar, Pravin R.,Kantam, Mannepalli Lakshmi,Bhargava, Suresh
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supporting information
p. 150 - 153
(2016/12/06)
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- Method for catalyzing cross coupling reaction of Suzuki with palladium magnesium aluminum class layered double hydroxides (LDHs)
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The invention discloses a method for catalyzing cross coupling reaction of Suzuki with palladium magnesium aluminum class layered double hydroxides (LDHs). The method includes that aryl halide and arylboronic acid are taken as raw materials, PdMgAl-LDHs are taken as a catalyst, and biphenyl compounds are reacted and generated under the condition that the phase transfer catalyst, alkali, additives and solvents exist. The catalyst is featured in that palladium is directly bonded on the slabs of the layered double hydroxides with even distribution and good stability. With the method, cross coupling reaction of Suzuki can be efficiently catalyzed, the catalyst is simple in preparation, easy to be regenerated and reusable, and pollution of the palladium on terminal product and environment is effectively reduced.
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Paragraph 0086-0088
(2017/07/19)
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- Activation of aryl chlorides in water for Suzuki coupling with a hydrophilic salen-Pd(II) catalyst
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For exploiting aqueous condition, we have designed a simple water-soluble palladium Schiff-base catalyst for Suzuki-Miyaura reactions of aryl halides with arylboronic acids. The reactions could be performed in neat water with aryl bromides and iodides at room temperature and with aryl chlorides at 100 °C. Good-to-excellent yields of cross-coupling products were obtained with a diverse range of aryl halides including heteroaryl halides. Interestingly, the homogeneous catalyst could be conveniently recycled with aryl bromides or chlorides for at least four times, although a progressive decrease in the product yields were noticed.
- Shahnaz, Nasifa,Puzari, Amlan,Paul, Bidisha,Das, Pankaj
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- Synthesis and evaluation of antitubercular activity of fluorinated 5-aryl-4-(hetero)aryl substituted pyrimidines
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Various 5-(fluoroaryl)-4-(hetero)aryl substituted pyrimidines have been synthesized based on the Suzuki cross-coupling and nucleophilic aromatic substitution of hydrogen (SNH) reactions starting from commercially available 5-bromopyr
- Verbitskiy, Egor V.,Baskakova, Svetlana A.,Kravchenko, Marionella A.,Skornyakov, Sergey N.,Rusinov, Gennady L.,Chupakhin, Oleg N.,Charushin, Valery N.
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p. 3771 - 3780
(2016/07/20)
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- A new route towards dithienoquinazoline and benzo[f]thieno[3,2-h]quinazoline systems using Pd-catalyzed intramolecular cyclization under microwave irradiation
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A novel synthetic route to novel thienoacene systems bearing a fused pyrimidine ring is proposed. The commercially available 5-bromopyrimidine is used as the starting material to obtain various dithienoquinazoline and benzo[f]thieno[3,2-h]quinazoline syst
- Verbitskiy, Egor V.,Rusinov, Gennady L.,Chupakhin, Oleg N.,Charushin, Valery N.
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p. 204 - 216
(2016/07/06)
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- Excellent Suzuki–Miyaura catalytic activity of a new Pd(II) complex with sulfonamide–Schiff base ligand
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A new air-stable Pd(II) complex containing a sulfonamide–Schiff base ligand has been synthesized, characterized and investigated as a catalyst for the Suzuki–Miyaura reactions of aryl halides with arylboronic acids. Theoretical calculations (B3LYP) and spectroscopic evidence suggest that the sulfonamide–Schiff base coordinates to the Pd centre through sulfonamide nitrogen (?SO2NH2) rather than imine (?CH?N). The complex shows excellent cross-coupling activity with aryl bromides in water at room temperature and aryl chlorides in isopropanol at 60°C. Copyright
- Banik, Biplab,Tairai, Archana,Bhattacharyya, Pradip K.,Das, Pankaj
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p. 519 - 523
(2016/07/16)
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- In situ generated and stabilized Pd nanoparticles by N2,N4,N6-tridodecyl-1,3,5-triazine-2,4,6-triamine (TDTAT) as a reactive and efficient catalyst for the Suzuki-Miyaura reaction in water
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In situ generated Pd nanoparticles in the presence of N2,N4,N6-tridodecyl-1,3,5-triazine-2,4,6-triamine (TDTAT) were found to be an efficient catalyst for the Suzuki-Miyaura coupling reaction in water. It seems that TDTAT not only acts as a ligand for stabilization of the produced nanoparticles, but also as a surfactant to facilate the reaction in water, and reduces Pd(ii) to Pd(0). The TEM analysis of the reaction mixture showed that Pd nanoparticles with an average size of ~5 nm are produced, which act as an efficient catalyst in the Suzuki-Miyaura coupling reaction.
- Iranpoor, Nasser,Rahimi, Sajjad,Panahi, Farhad
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p. 3084 - 3090
(2016/01/16)
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- Air-Stable Triazine-Based Ni(II) PNP Pincer Complexes As Catalysts for the Suzuki-Miyaura Cross-Coupling
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Air-stable, thermally robust, and well-defined cationic Ni(II) PNP pincer complexes based on the 2,4-diaminotriazine scaffold are described. These complexes are active catalysts for the Suzuki-Miyaura cross-coupling of a wide range of aryl, heteroaryl (including benzoxazole, thiazole, pyridine, pyrimidine, thiazole), primary and secondary alkyl halides, and pseudohalides with different organoboronate reagents giving excellent to good isolated yields. Neutral deprotonated complexes seem to play a key role in the catalytic process.
- Mastalir, Matthias,St?ger, Berthold,Pittenauer, Ernst,Allmaier, Günter,Kirchner, Karl
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supporting information
p. 3186 - 3189
(2016/07/14)
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- Facile synthesis of palladium nanoparticles supported on silica: An efficient phosphine-free heterogeneous catalyst for Suzuki coupling in aqueous media
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A convenient one-step method for synthesizing highly dispersed palladium nanoparticles supported on silica, without taking assistance from any external reductant or stabilizer, has been developed. The supported nanoparticles were characterized by N2-adsorption desorption, XRD, HRTEM, SEM-EDX, XPS, ICP analyses and applied as catalyst for Suzuki-Miyaura reactions of aryl halides. The reactions with aryl bromides were performed in neat water at room temperature; while the reactions with aryl chlorides were conducted in aqueous-ethanol at 90?°C. The catalyst could be reused at least three times without compromising with its activity, however from the fourth cycle a progressive decrease in yield was noticed. No aggregation of NPs was observed by the TEM analysis of the six-time used catalyst.
- Sahu, Debojeet,Silva, Ana R.,Das, Pankaj
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- Highly water-dispersible magnetite nanoparticle supported-palladium-β-cyclodextrin as an efficient catalyst for Suzuki-Miyaura and Sonogashira coupling reactions
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We reported here a novel highly water-dispersible and recoverable magnetite supporting a palladium-β-cyclodextrin complex as an efficient catalyst in Suzuki-Miyaura and Sonogashira carbon-carbon coupling reactions. The magnetite nanoparticle supporting catalyst was characterized by FT-IR, CHN, EDS, TGA, XRD, TEM and VSM. The prepared catalyst displayed excellent activity for a wide range of substrates in aqueous solution under mild reaction conditions. The reusability of the magnetite supporting palladium-β-cyclodextrin nanocatalyst was successfully examined five times with a slight loss of catalytic activity.
- Salemi,Kaboudin,Kazemi,Yokomatsu
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p. 52656 - 52664
(2016/06/14)
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- Pd(II)-β-cyclodextrin complex: Synthesis, characterization and efficient nanocatalyst for the selective Suzuki-Miyaura coupling reaction in water
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Herein we report the preparation, characterization and the catalytic ability of novel Pd(II)-β-cyclodextrin complex as an efficient nanocatalytic system for the Suzuki-Miyaura carbon-carbon (C-C) coupling reaction in water. The presented novel Pd(II)-β-cyclodextrin complex catalyst was characterized by TGA, FT-IR, XRD, NMR and atomic absorption analysis. Also, by using the Pd(II)-β-CD complex as a homogeneous catalyst, we have developed an efficient protocol for suzuki-Miyaura coupling reaction of aryl boronic acids with aryl halides in neat water with high turnover frequencies (TOFs) for the synthesis of unsymmetrical biaryls. The catalyst can be recycled and reused multiple times to catalyze the coupling reaction.
- Kaboudin, Babak,Salemi, Hadi,Mostafalu, Ramin,Kazemi, Foad,Yokomatsu, Tsutomu
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p. 195 - 199
(2016/07/06)
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- In situ-generated nano-palladium-catalyzed ligand-free Suzuki-Miyaura reaction of potassium aryltrifluoroborates at room temperature
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A mild and simple protocol is described for the palladium-catalyzed ligand-free Suzuki-Miyaura reaction of potassium aryltrifluoroborates in aqueous ethanol at room temperature. Palladium nanoparticles are generated in situ in the reaction and demonstrate high activity towards a wide range of aryl bromides and potassium aryltrifluoroborates, providing biphenyls in good to excellent yields. Interestingly, only 1 equiv of K2CO3 is used in this catalytic system. Moreover, the key biaryl intermediate of 2-cyano-4′-methylbiphenyl within valsartan is prepared in a 95% yield after 2 h.
- Liu, Chun,Li, Xinmin,Gao, Zhanming,Wang, Xinnan,Jin, Zilin
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supporting information
p. 3954 - 3959
(2015/06/02)
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- A novel polymer containing phosphorus-nitrogen ligands for stabilization of palladium nanoparticles: An efficient and recyclable catalyst for Suzuki and Sonogashira reactions in neat water
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A new polymer containing phosphorus and nitrogen ligands was successfully synthesized, characterized and used for the stabilization of highly monodispersed palladium nanoparticles having an average diameter of 2-3 nm. The thermally stable heterogeneous catalyst was successfully applied in Suzuki-Miyaura and copper-free Sonogashira-Hagihara coupling reactions of aryl halides under low palladium loading conditions. Reactions were proceeded in neat water without using any organic co-solvents. The catalyst was successfully recycled for the sample Suzuki-Miyaura reaction nine consecutive times with small drop in catalytic activity.
- Gholinejad,Hamed,Biji
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p. 14293 - 14303
(2015/08/24)
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- Palladium complex containing two sterically hindered ligands as highly efficient catalyst for Suzuki-Miyaura reaction
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A new palladium(II) complex containing two sterically hindered ligands, a P,P-bonded diphosphine and N,N-bonded Schiff base, within the same coordination sphere has been synthesized and investigated as a catalyst for the Suzuki-Miyaura cross-coupling reactions of aryl halides with arylboronic acids. The reaction was highly efficient with aryl bromides in water at room temperature and aryl chlorides in dimethylformamide under relatively mild conditions. Excellent yields of coupling products were obtained for a wide range of aryl halides including heteroaryl halides with a low loading of catalyst.
- Shahnaz, Nasifa,Das, Pankaj
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p. 829 - 833
(2016/01/26)
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- Palladium-Schiff-base-silica framework as a robust and recyclable catalyst for Suzuki-Miyaura cross-coupling in aqueous media
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A silica supported palladium catalyst, Pd@imine-SiO2 was prepared by immobilizing Pd(OAc)2 onto silica gel through coordination of imine, generated via Schiff-base condensation between 3-aminopropyltriethoxysilane (APTES) functionalized silica gel and salicylaldehyde. The prepared catalyst was characterized by FT-IR, BET surface area measurements, XRD, SEM-EDX, EDS-mapping and ICP-AES analysis. The imine-based catalyst exhibited excellent activity in the Suzuki-Miyaura cross-coupling reactions of aryl bromides with arylboronic acids in iPrOH/H2O (1:1) at room temperature. The reaction proceeds under mild reaction conditions and the catalyst is recyclable, thus offering an environmentally benign alternative to the existing protocols.
- Begum, Tahshina,Mondal, Manoj,Gogoi, Pradip K.,Bora, Utpal
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p. 38085 - 38092
(2015/06/25)
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- Phosphine-stabilized Pd nanoparticles supported on silica as a highly active catalyst for the Suzuki-Miyaura cross-coupling reaction
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We have prepared a silica supported palladium nanocatalyst (PdNP@PPh2-SiO2) with high dispersion via a one-step reaction between commercially available 2-diphenylphosphinoethyl-functionalized silica gel (PPh2-SiO2) and PdCl2 without the assistance of an external reductant or stabilizer. The catalyst was well characterized by N2-adsorption, XRD, HRTEM, SEM-EDX and ICP analyses. The supported catalyst exhibited excellent activity for the Suzuki-Miyaura cross-coupling reactions of aryl halides (including aryl chlorides) with arylboronic acids. The facile synthesis of the catalyst combined with high product yields at relatively low catalyst loading (0.5 mol%) represents one of the most efficient silica supported heterogeneous systems for the Suzuki coupling of aryl chlorides. The catalyst could be reused several times without compromising its activity.
- Sahu, Debojeet,Das, Pankaj
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p. 3512 - 3520
(2015/02/05)
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- Magnetically-recoverable Schiff Base Complex of Pd (II) Immobilized on Fe3O4@SiO2 Nanoparticles: An Efficient Catalyst for Mizoroki-Heck and Suzuki-Miyaura Coupling Reactions
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The activity of Pd(II)-Schiff base complexmolecules grafted on the surface of Fe3O4@SiO2 particles were investigated in the palladium-catalyzed coupling reactions of aryl halides with alkenes (Mizoroki-Heck reaction) and phenylboronic acids (Suzuki-Miyaura reaction) in the absence of phosphorous ligands. This method shows notable advantages such as heterogeneous nature of the catalyst, excellent yields, short reaction times, easy preparation, simplicity of operation, and cleaner reaction profiles. The catalyst can be separated from the reaction mixture by applying a permanent magnet externally and can be reused for several times without significant loss of activity. Also, the amount of palladium leaching has been determined by ICP analysis.
- Esmaeilpour, Mohsen,Javidi, Jaber
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p. 614 - 626
(2018/01/18)
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- 2-(diphenylphosphino)pyridine platinum (I) and palladium (I) complex as an efficient binuclear catalyst for Suzuki-Miyaura coupling reaction in water under mild reaction conditions
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Binuclear complex of platinum (I) and palladium (I) showed superior activity in Suzuki-Miyaura coupling reaction of aryl halides with arylboronic acids compared to the sole palladium or platinum species. The catalyst showed good tolerance in water and coupling reactions were performed in water as a green solvent. Aryl iodides were reacted at room temperature and the reactions of aryl bromides were performed at 60 °C.
- Gholinejad, Mohammad,Shahsavari, Hamid R.,Razeghi, Mehran,Niazi, Maryam,Hamed, Fatemeh
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