- Transformation of Trifluorotoluenes Triggered by Titanium(IV) Chloride-Catalyzed Hydrodefluorination using Hydrosilanes
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The titanium tetrachloride-catalyzed hydrodefluorination reaction of trifluorotoluene derivatives was developed using triethylsilane as the reducing agent. The reaction produced various toluene derivatives with high chemoselectivities by means of readily accessible reagents. This hydrodefluorination process was extended to the intramolecular Friedel-Crafts benzylation reaction, furnishing polycyclic aromatics of various ring sizes in good yields.
- Yamada, Takayuki,Saito, Kodai,Akiyama, Takahiko
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- A highly efficient heterogeneous montmorillonite K-10-supported palladium catalyst for Suzuki-Miyaura cross-coupling reaction in aqueous medium
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A heterogeneous montmorillonite K-10-supported palladium triphenylphosphine catalyst is reported for the Suzuki-Miyaura cross-coupling reaction at room temperature. A library of electronically diverse aryl bromides and arylboronic acids underwent the cross-coupling reaction at very good rates in aqueous solvent. The reusability of the catalyst was also examined and it was found to be effective up to three catalytic cycles.
- Gogoi, Ankur,Chutia, Sankar Jyoti,Gogoi, Pradip K.,Bora, Utpal
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- Pillar[5]arene-based N-heterocyclic carbene ligand for Pd-catalysed Suzuki reaction
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A pillar[5]arene-based N-heterocyclic carbene ligand was prepared by reaction of bromoethoxy pillar[5]arene with excess 1-methylimidazole at 130?°C in the absence of solvent and used as a catalyst for the Suzuki coupling reaction. Excellent yields were obtained when the Suzuki reactions were carried out under ambient atmosphere in ethanol, employing 0.2?mol% ligand, 1?mol% PdCl2(CH3CN)2 and 1.5?mmol of K2CO3. The novel pillar[5]arene-based imidazolium salt is a promising material for the construction of highly active supramolecular catalytic systems.
- Xiao, Xue-Dong,Liu, Jia-Qi,Bai, Ya-Li,Wang, Rui-Hua,Wang, Jun-Wen
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- Reusable Pd nanoparticles immobilized on functional ionic liquid co-polymerized with styrene for Suzuki reactions in water-ethanol solution
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Co-polymer of 3-(2,3-dihydroxypropyl)-1-vinylimidazolium chloride and styrene was synthesized and used as a support of Pd nanoparticles. The Pd@poly-Sty-co-diOH-Cl catalyst can efficiently catalyze Suzuki reactions for a wide range of aryl iodides and bromides with 0.05 mol % Pd at 70 °C in water-ethanol solution under air, and the catalyst can be recycled and reused for several times without significant loss of activity.
- Wang, Jiayi,Song, Gonghua,Peng, Yanqing
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- Engineering of highly active Au/Pd supported on hydrogenated urchin-like yolk@shell TiO2 for visible light photocatalytic Suzuki coupling
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Efficient smart photocatalysts and their surface engineering are necessary for the effective conversion of light energy into chemical energy in photocatalyzed organic reactions. Herein, we designed a hydrogenated urchin-like yolk@shell TiO2 structure decorated with Au and Pd nanoparticles (HUY@S-TOH@AuPd) as a robust photocatalyst for C-C coupling reactions. The resulting architecture exhibits considerable photocatalytic performance in Suzuki coupling reactions under visible light irradiation with a turnover frequency (TOF) value as high as 7095 h-1. The beauty of this engineered structure lies on the following four points: (I) the urchin-like structure provided a large accessible surface area for high light harvesting as well as high noble metal anchoring; (II) the yolk@shell mesoporous architecture improved the absorption of light by multiple scattering; (III) the presence of Ti3+ species on the surface of TiO2 decreased the band gap of the structure to the visible region; (IV) the enriched electron density of Pd through the injection of hot electrons from Au as well as the flow of electrons from the titanium dioxide semiconductor to the metals accelerated the rate-determining step. The merging of bimetallic plasmonic nanoparticles and urchin like yolk-shell hydrogenated titanium dioxide architecture can open an avenue for designing photocatalysts with high stability and promising activity as well as high direct harvesting of visible light for a broad range of photocatalytic organic reactions.
- Rohani, Sahar,Ziarati, Abolfazl,Ziarani, Ghodsi Mohammadi,Badiei, Alireza,Burgi, Thomas
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- Desulfinylative Pd-catalyzed coupling reaction of arenediazonium salt with aryl sulfinates to give unsymmetrical biaryls
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An efficient route for the synthesis of unsymmetrical biaryls was developed via palladium catalyzed reaction of arenediazonium salts and aryl sulfinates under inert atmosphere. This synthesis involves cascade processes. Tetrabutylammonium iodide was used as an iodide source for in situ formation of aryl iodide, followed by desulfinylative cross-coupling reaction between aryl sulfinates and aryl iodides. A wide range of biaryls were selectively prepared in one pot from simple substrates in good to excellent yields.
- Gund, Sitaram Haribhau,Balsane, Kishor Eknath,Nagarkar, Jayashree Milind
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- Mesoporous palladium-copper ferrites as highly efficient and magnetically separable catalysts for Suzuki coupling reaction
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Mesoporous Cu-Pd ferrites were prepared by using MCM-41 and SBA-15 mesoporous molecular sieves as hard templates and well characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ICP-atomic emission spectroscopy, N2 adsorption-desorption and X-ray photoelectric spectroscopy (XPS). Compared with samples prepared by the sol-gel auto-combustion methods, the as-prepared mesoporous ferrites have shown uniform pore size and much higher specific surface areas. The samples showed a remarkably high activity in connection with the Suzuki coupling reaction, especially Cu0.99Pd0.01Fe2O4 prepared by using MCM-41 as template obtained an excellent TOF as high as 36.9 × 103 h-1 and no obvious decrease in the activity was observed after ten consecutive runs.
- Tong, Jinhui,Su, Lingdi,Bo, Lili,Cai, Xiaodong,Zhang, Qianping,Wang, Qizhao
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- Pd nanoparticles immobilized on the magnetic silica–chitosan nanocomposite (NiFe2O4@SiO2@CS-Pd NPs) promoted the biaryl synthesis
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NiFe2O4 nanoparticles have been prepared by co-precipitation procedure and coated with SiO2 following the St?ber process. Then, chitosan was covalently connected with silica to provide an excellent stabilizer and biosupport for the immobilization of Pd nanoparticles. This magnetic bionanocatalyst was characterized by Fourier transform infrared spectroscopy, field-emission scanning electron microscope, transmission electron microscope, energy-dispersive X-ray, X-ray powder detection, vibrating sample magnetometer, inductively coupled plasma atomic emission spectroscopy techniques and CHN analysis. The NiFe2O4@SiO2@CS-Pd NPs exhibited high activity for the Suzuki coupling reactions of various aryl halides with arylboronic acids. Moreover, this catalyst could be recovered magnetically and recycled for nine times without significant loss of its activity.
- Rafiee, Fatemeh,Hosseini, S. Azam
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- Palladium(II) thiosemicarbazone-catalyzed Suzuki-Miyaura cross-coupling reactions of aryl halides
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A new air-and moisture-stable palladium(II) complex bearing pyridoxal thiosemicarbazone ligand has been synthesized. The synthesized complex was characterized by analytical and spectral methods. The molecular structure of the complex was confirmed by X-ray diffraction method. The palladium(II) complex was used as potential catalyst for Suzuki-Miyaura coupling reaction of several aryl halides under optimized conditions.
- Pandiarajan, Devaraj,Ramesh, Rengan,Liu, Yu,Suresh, Rajamanickam
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- Structuring Pd Nanoparticles on 2H-WS2 Nanosheets Induces Excellent Photocatalytic Activity for Cross-Coupling Reactions under Visible Light
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Effective photocatalysts and their surface engineering are essential for the efficient conversion of solar energy into chemical energy in photocatalyzed organic transformations. Herein, we report an effective approach for structuring Pd nanoparticles (NPs) on exfoliated 2H-WS2 nanosheets (WS2/PdNPs), resulting in hybrids with extraordinary photocatalytic activity in Suzuki reactions under visible light. Pd NPs of different sizes and densities, which can modulate the photocatalytic activity of the as-prepared WS2/PdNPs, were effectively structured on the basal plane of 2H-WS2 nanosheets via a sonic wave-assisted nucleation method without any reductants at room temperature. As the size of Pd NPs on WS2/PdNPs increased, their photocatalytic activity in Suzuki reactions at room temperature increased substantially. In addition, it was found that protic organic solvents play a crucial role in activating WS2/PdNPs catalysts in photocatalyzed Suzuki reactions, although these solvents are generally considered much less effective than polar aprotic ones in the conventional Suzuki reactions promoted by heterogeneous Pd catalysts. A mechanistic investigation suggested that photogenerated holes are transferred to protic organic solvents, whereas photogenerated electrons are transferred to Pd NPs. This transfer makes the Pd NPs electron-rich and accelerates the rate-determining step, i.e., the oxidative addition of aryl halides under visible light. WS2/PdNPs showed the highest turnover frequency (1244 h-1) for photocatalyzed Suzuki reactions among previously reported photocatalysts.
- Raza, Faizan,Yim, Dabin,Park, Jung Hyun,Kim, Hye-In,Jeon, Su-Ji,Kim, Jong-Ho
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- Room-temperature Suzuki-Miyaura reaction catalyzed by palladium nanoparticles in lactate-anion ionic liquid
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A palladium nanoparticle catalyst (PdNPs[Bmim]Lac) has been prepared by a simple, mild and efficient chemical approach using 1-butyl-3-methylimidazolium lactate ([Bmim]Lac) ionic liquid) as a stabilizer. This catalyst exhibits excellent activity, stability, recyclability and simple manipulation in Suzuki-Miyaura reactions at room temperature in air.
- Wang, Furong,Tang, Sisi,Ma, Hao,Wang, Lefu,Li, Xuehui,Yin, Biaolin
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- Sustainable H2O/ethyl lactate system for ligand-free Suzuki-Miyaura reaction
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A sustainable catalyst system consisted of H2O/ethyl lactate (EL), Pd(OAc)2 and K2CO3 has been developed as a generally applicable protocol for Suzuki-Miyaura reactions using various aryl bromides and iodides to incorporate arylboronic acids under ligand-free conditions. This protocol is advantageous owing to the employment of water and non-toxic, biomass available ethyl lactate as green media. In addition, as a co-solvent with water, ethyl lactate displayed evident superiority over conventional polar organic solvents such as DMF, DMSO and dioxane etc., which implied the additional potential function of EL as a ligand in these reactions.
- Wan, Jie-Ping,Wang, Chunping,Zhou, Rihui,Liu, Yunyun
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- DNA as a bioligand supported on magnetite for grafting palladium nanoparticles for cross-coupling reaction
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The utilization of deoxyribonucleic acid (DNA) in nanotechnology is a promising area of research wherein the distinct properties of DNA are exploited for the design and development of new materials and applications. The biodegradability and natural profusion of DNA makes it highly suitable for use in various fields. In this report, we have treated DNA as a bioligand, supported on functionalized magnetite for the grafting of palladium (Pd) nanoparticles to make Pd-DNA bio-nanocatalyst. The Pd-DNA was subjected to Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Brunauer–Emmett–Teller, energy dispersive X-ray spectroscopy, vibrating sample magnetometry, X-ray photoelectron spectroscopy, and inductively coupled plasma optical emission spectrometry analysis. The prepared Pd-DNA was found to be highly efficient in catalyzing Suzuki–Miyaura cross-coupling reaction with excellent yields when compared with commercially available palladium-based catalysts. Also, the Pd-DNA could be easily recovered from the reaction mass using an external magnet and recycled up to six times without substantial loss of activity. Furthermore, Felbinac, a non-inflammatory drug, was synthesized in quantitative yields using the Pd-DNA bio-nanocatalyst.
- Kandathil, Vishal,Kempasiddaiah, Manjunatha,Nataraj, Sanna Kotrappanavar,Patil, Siddappa A.,Somappa, Sasidhar Balappa
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- Arylation of non-activated C-Cl bond with Grignard reagents catalyzed by pincer [PCP]-nickel complexes
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A series of pincer Ni(II) complexes were prepared and utilized in the cross-coupling reaction of non-activated aryl chlorides with Grignard reagents (The Kumada reaction). Catalytic studies revealed that complex 5 ([Ph-PNCNP-Ph]-Ni-Cl) showed the highest catalytic activity for the cross-coupling reaction in the presence of 2 mol% catalyst under mild reaction condition.
- Sun, Yunqiang,Li, Xiaoyan,Sun, Hongjian
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- Palladium nanoparticles supported on functional ionic liquid modified magnetic nanoparticles as recyclable catalyst for room temperature Suzuki reaction
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Palladium nanoparticles were successfully immobilized on amine functionalized ionic liquid modified magnetic nanoparticles leading to a magnetically recoverable Pd catalyst, which exhibits high catalytic activity in the Suzuki coupling reaction at room temperature. 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.
- Wang, Jiayi,Xu, Beiling,Sun, Haiyang,Song, Gonghua
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- Synthesis, Palladium(II) Complexes, and Catalytic Use of a Phosphanylferrocene Ligand Bearing a Guanidinium Pendant
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A polar phosphanylferrocene donor equipped with a hydrophilic guanidinium pendant, Ph2PfcCH2NHC(NH)NH2·HCl (1·HCl; fc = ferrocene-1,1′-diyl), has been prepared from the corresponding amine hydrochloride, Ph2PfcCH2NH2·HCl (2·HCl), and studied as a ligand for PdII. The reactions of 1·HCl with [PdCl2(MeCN)2] in 1:1 and 1:2 Pd/ligand ratios led to an unexpected zwitterionic complex, [PdCl3(1H-κP)] (3), and the expected bis(phosphane) complex, trans-[PdCl2(1H-κP)2]Cl2(4), which were structurally characterized. The defined and air-stable solvated complex 3·Me2CO and the in situ generated Pd(OAc)2/1·HCl system were found to be active catalysts for the Suzuki–Miyaura cross-coupling of anionic triolborates with aryl bromides, giving the corresponding biphenyls. These reactions, which do not require the presence of an additional base, were advantageously performed in aqueous ethanol, and the coupling products were isolated in good to excellent yields.
- Bárta, Ond?ej,Císa?ová, Ivana,?těpni?ka, Petr
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- Synthesis, characterization and evaluation of bulky bis(pyrazolyl)palladium complexes in Suzuki-Miyaura cross-coupling reactions
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Pyrazole-containing compounds have been used in recent times as ligands to stabilize metal complexes used as pre-catalysts in cross-coupling reactions. With various substituents at various positions in the pyrazole ring, the overall electrophilic and steric properties of the metal complexes can be fine-tuned. Herein, we report the synthesis of bulky pyrazole-based ligands by condensation of methyl 4-(bromomethyl)benzoate or benzyl bromide with various substituted pyrazole compounds. These ligands were utilised in the synthesis of bis(pyrazolyl)palladium(ii) complexes. The complexes' catalytic activity in Suzuki-Miyaura cross-coupling reactions was evaluated. Phenyl bearing pre-catalyst 7, at a catalyst loading of 0.33 mol%, successfully converted 98% of bromobenzene and phenylboronic acid to biphenyl in 4 h at 140 °C, while the tertiary butyl bearing pre-catalyst 8 converted up to 81% of the same substrates to biphenyl. An increase in conversion was seen for all pre-catalysts when an electron-withdrawing substituent was present on the aryl halide substrate, and the opposite was observed when the electron-withdrawing group was present on the phenyl boronic acid.
- Ocansey, Edward,Darkwa, James,Makhubela, Banothile C. E.
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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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- Bimetallic Ni–Pd Synergism—Mixed Metal Catalysis of the Mizoroki-Heck Reaction and the Suzuki–Miyaura Coupling of Aryl Bromides
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Abstract: A combination of Pd and Ni complexes activated aryl bromides for the thermal Mizoroki-Heck reaction and Suzuki coupling giving high yields in short reaction times. A thermal redox mechanism probably occurs whereby Ni complex transfers electron and reduces the Pd (II) to Pd (0) which then takes the reactants through the standard protocol of oxidative-addition, migratory insertion and reductive elimination, typical for the Mizoroki-Heck reaction and the Suzuki coupling. Graphic Abstract: [Figure not available: see fulltext.]
- Kashid, Abhijit A.,Patil, Dharmaraj J.,Mali, Ramling D.,Patil, Vijay P.,Neethu,Meroliya, Heena K.,Waghmode, Shobha A.,Iyer, Suresh
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p. 353 - 358
(2020/08/05)
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- Pd-Catalysed Suzuki-Miyaura cross-coupling of aryl chlorides at low catalyst loadings in water for the synthesis of industrially important fungicides
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The Suzuki-Miyaura coupling reaction of electron-poor aryl chlorides in the synthesis of crop protection-relevant active ingredients in water is disclosed. Optimisation of the reaction conditions allowed running the reaction with 50 ppm of Pd-catalyst loading without an additional organic solvent in the cross-coupling reaction step in short reaction times. The system was optimised for the initial cross-coupling step of the large scale produced fungicides Boscalid, Fluxapyroxad and Bixafen up to 97% yield. It is also shown that the Suzuki-Miyaura reaction can be easily scaled up to 50 g using a simple product separation and purification using environmentally benign solvents in the work-up. To show the usability of this method, it was additionally applied in the three-step synthesis of the desired active ingredients.
- Goetz, Roland,Hashmi, A. Stephen K.,Orecchia, Patrizio,Petkova, Desislava Slavcheva,Rominger, Frank,Schaub, Thomas
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supporting information
p. 8169 - 8180
(2021/11/01)
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- Bimetallic nano alloy architecture on a special polymer: Ni or Cu merged with Pd for the promotion of the Mizoroki–Heck reaction and the Suzuki–Miyaura coupling
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Abstract: Novel Ni-Pd and Cu-Pd bimetallic nano alloys was designed and heterogenized on the highly robust ABPBI [poly(2,5-benzimidazole)] polymer in high yields using NaBH4 as reducing agent. These were versatile ligand free catalysts for the Mizoroki–Heck reaction and Suzuki–Miyaura coupling. The bimetallic Ni-Pd-ABPBI catalyst for the Mizoroki–Heck reaction of 4-iodo anisole could be recycled 5 times with high yields. Aryl bromides could also be activated for the Mizoroki–Heck reaction using Cu-Pd-ABPBI NP catalysts, with moderate yields. Graphic abstract: Synopsis Novel bimetallic Ni-Pd and Cu-Pd nano alloys, heterogenized on the robust ABPBI [poly(2,5-benzimidazole)] polymer using NaBH4 as reducing agent, is described. These were versatile ligand free, noble metal conservative catalysts, for the Mizoroki–Heck reaction and the Suzuki–Miyaura coupling. Aryl bromides were activated for the Mizoroki–Heck reaction using the Cu-Pd-ABPBI catalyst.[Figure not available: see fulltext.]
- Patil, Vijay P,Kashid, Abhijit A,Solanki, Bhanupratap S,Kharul, Ulhas K,Iyer, Suresh
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- Oxime ligands for Pd catalysis of the Mizoroki–Heck reaction, Suzuki–Miyaura coupling & annulation reactions
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Monodentate and bidentate chelating oximes are readily available ligands for the Pd catalysis of the Mizoroki–Heck reaction and the Suzuki coupling. High yields were obtained in the Suzuki coupling in aqueous dioxane with TBABr as additive. The oximes can be easily synthesized from the corresponding ketones or aldehydes and thus provide a very large number of nitrogen-based ligands. They have the advantage of not undergoing oxidative degradation, common for phosphine ligands. Chelating oximes with Pd(OAc)2, activate aryl iodides to give high yields of the substitution products in the Mizoroki–Heck reactions as well as the Suzuki coupling. Acetophenone oxime ligand with Pd(OAc)2, catalyzed the reaction of aryl iodides with 1,2-disubstituted alkenes in moderate to high yields. As a test example, the LaRock indole annulation and synthesis of isocoumarin were achieved with acetophenone oxime ligand and Pd(OAc)2 in high yields.
- Bangar, Pronnoy G.,Nahide, Pradip D.,Meroliya, Heena K.,Waghmode, Shobha A.,Iyer, Suresh
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supporting information
p. 308 - 316
(2020/10/06)
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- Anchored PdCl2 on fish scale: an efficient and recyclable catalyst for Suzuki coupling reaction in aqueous media
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PdCl2 anchored on fish scale (FS) complex were intended to a heterogeneous catalyst for ligand-free Suzuki coupling reaction in aqueous media. The catalyst FS-PdCl2 was characterized by FT-IR, powder XRD, XPS and SEM. FS-PdCl2 complex has been successfully implemented for Suzuki coupling reactions of various halogenated aromatics with arylboronic acid to provide the corresponding biaryl compounds under environmentally friendly conditions (40 °C, water solvent). Moreover, the efficient catalyst shows excellent stability and recyclability, and its catalytic activity without any decrease after 8 times consecutive reused.
- Yang, Quanlu,Yang, Fawang,Zhang, Ying,Hou, Juanjuan,Li, Jiankun,Cheng, Jinkui,Wu, Shang,Zhan, Huiying,Zhang, Xinghui,Shi, Haixiong
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supporting information
(2020/12/25)
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- Hexagonal Boron Nitride Supported N-Heterocyclic Carbene-Palladium(II): A New, Efficient and Recyclable Heterogeneous Catalyst for Suzuki–Miyaura Cross-Coupling Reaction
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Abstract: In this study, a new stable and powerful hexagonal boron nitride supported N-heterocyclic carbene-palladium(II) complex (h-BN@NHC-Pd) heterogeneous catalyst was designed and synthesized. The structure of the h-BN@NHC-Pd heterogeneous catalyst was characterized by various techniques such as Fourier transform infrared spectra (FT-IR), ultraviolet–visible spectroscopy (UV–Visible), inductively coupled plasma-optical emission spectroscopy (ICP-OES), energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller surface area analysis (BET). Then catalytic activity of h-BN@NHC-Pd heterogeneous catalyst was studied in the Suzuki–Miyaura cross-coupling reactions between aryl halides and arylboronic acids in aqueous medium at room temperature. The effects of varying solvents, bases, temperature, time and catalytic ratios on the performance of the Suzuki–Miyaura cross-coupling reaction were investigated. Moreover, h-BN@NHC-Pd heterogeneous catalyst could be easily recovered through simple filtration or centrifugation method and could be reused five times without significant loss of its catalytic efficiency. Furthermore, stability of the h-BN@NHC-Pd heterogeneous catalyst after recycling was confirmed through FESEM and FT-IR techniques. The h-BN@NHC-Pd heterogeneous catalyst shows remarkable advantages such as simplicity of operation, excellent yields, short reaction times, heterogeneous nature, easily separable and high stability without leaching. Graphic Abstract: A new stable and powerful hexagonal boron nitride supported N-heterocyclic carbene-palladium(II) complex (h-BN@NHC-Pd) heterogeneous catalyst was designed, synthesized, characterized and catalytic activity was studied in the Suzuki–Miyaura cross-coupling reactions. [Figure not available: see fulltext.]
- Antony, Arnet Maria,Kandathil, Vishal,Kempasiddaiah, Manjunatha,Sasidhar,Patil, Shivaputra A.,Patil, Siddappa A.
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p. 1293 - 1308
(2020/10/06)
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- Anchored Pd(0) Nanoparticles on Synthetic Talc for the Synthesis of Biaryls and a Precursor of Angiotensin II Inhibitors
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The palladium-catalyzed Suzuki-Miyaura cross-coupling reaction is one of the most important and efficient reactions to prepare a variety of organic compounds, including biaryls. Despite the overwhelming number of reports related to this topic, some methodological difficulties persist in terms of catalyst handling, recovery, and reuse, as well as the reaction media. This work reports the rational design of new, efficient, cost-effective, and reusable palladium catalysts supported on synthetic talc for the Suzuki-Miyaura reaction. From the results, key points were identified: both designed catalysts accelerated the reaction in EtOH and an open-flask setup, affording moderate to excellent yields within a short time (e.g., 30 min) even for deactivated aryl halides; the protocol can be applied to a great number of both cross-coupling partners, showing an excellent functional group tolerance; the catalysts can be recovered and reused without significant loss of activity. This protocol was used for the synthesis of a precursor of angiotensin II inhibitors such as valsartan, losartan, irbesartan, and telmisartan.
- Dos Santos, Beatriz F.,Da Silva, Beatriz A. L.,De Oliveira, Aline R.,Sarragiotto, Maria H.,Domingues, Nelson Luís C.
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p. 933 - 942
(2020/12/28)
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- N-Aroylsulfonamide-Photofragmentation (ASAP)-A Versatile Route to Biaryls
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The photochemical fragmentation of N-aroylsulfonamides 9 (ASAP) is a powerful method for the preparation of various biaryls. Compounds 9 are easily accessible in two steps from amines by treatment with arenesulfonyl chlorides and aroyl chlorides. Many of these compounds were prepared for the first time. The irradiation takes place in a previously developed continuous-flow reactor using inexpensive UVB or UVC fluorescent lamps. Isocyanates and sulphur dioxide are formed as the only by-products. The ASAP tolerates a variety of functional groups and is even suited for the preparation of phenylnaphthalenes and terphenyls. The ASAP mechanism was elucidated by interaction of photophysical and quantum chemical (DFT) methods and revealed a spirocyclic biradical as key intermediate.
- Wessig, Pablo,Krebs, Saskia
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supporting information
p. 6367 - 6374
(2021/09/29)
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- Pd-NHCs Enabled Suzuki-Miyaura Cross-Coupling of Arylhydrazines via C–N Bond Cleavage
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We describe a highly efficient protocol for cross-coupling of phenylhydrazines with arylboronic acids by Pd-NHCs under aerobic reaction condition. A series of well-defined Pd-NHCs complexes were evaluated and the relationship between the structure and the catalytic properties was investigated. It was disclosed that the Pd-PEPPSI-IPr proved to be the robust precatalyst, providing access to a range of (hetero)biaryls in good to excellent yields.
- Zeng, Xiao-Xiao,Li, Dong-Hui,Zhou, Zhen,Xu, Chang,Liu, Feng-Shou
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supporting information
(2021/03/01)
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- Bulky α-diimine palladium complexes supported graphene oxide as heterogeneous catalysts for Suzuki-Miyaura reaction
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To explore high efficiency of the Suzuki-Miyaura reactions, an easily prepared heterogeous palladium precatalysts bearing sterically bulky α-diimine was covalently supported on graphene oxide (GO). The characterization of supported palladium complex was discussed in detail. A simple and efficient protocol for Pd-catalyzed cross coupling was described, which revealed that the bulky α-diimine ligand is crucial to promote the CAr-CAr transformation. This immobilized system provides a straightforward access to a wide range of aryl bromides with excellent functional groups tolerance.
- Liang, Ying,Liu, Feng-Shou,Liu, Ning,Qiao, NiNa,Wang, ShaoHua
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- Immobilized Pd on Eggshell Membrane: A powerful and recyclable catalyst for Suzuki and Heck cross-coupling reactions in water
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A stable heterogeneous palladium catalysts, the waste eggshell membrane (ESM) anchored Pd complex, was synthesized by a simple and green technique. The catalyst obtained can display an outstanding catalytic activity for Suzuki and Heck coupling reactions in water media. The reactions of various aryl halides with aryl boronic acids and terminal alkenes provided the corresponding products in moderate to excellent yields. More importantly, this novel and efficient catalyst with high stability can be easily reused for at least twelve times with no decrease of the catalytic activity, performing an endurable and wide tolerance of the substrates. Facile synthesis, high catalytic activity, and recyclability make these catalysts interesting for further studies.
- Wu, Shang,Jiang, Hongyan,Zhang, Hong,Zhao, Lianbiao,Yuan, Peilin,Zhang, Ying,Su, Qiong,Wang, Yanbin,Wu, Lan,Yang, Quanlu
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- Palladium-Catalyzed Three-Component Coupling of Ynamides
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A palladium-catalyzed regioselective three-component coupling of ynamides was developed. The reaction proceeded smoothly to furnish the desired products when carried out at 70 °C in acetonitrile/water with potassium carbonate in the presence of 2.5 mol percent Pd2(dba)3·CHCl3 without a ligand. Various iodides and boronic acids were used in this reaction, and a carbon-carbon bond was formed with satisfactory regioselectivity from the ynamides.
- Wakamatsu, Hideaki,Takahashi, Ayano,Ishii, Ayaka,Kikuchi, Youhei,Sasaki, Madoka,Saito, Yukako,Natori, Yoshihiro,Yoshimura, Yuichi
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supporting information
p. 5299 - 5303
(2020/07/08)
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- para-Selective arylation and alkenylation of monosubstituted arenes using thianthreneS-oxide as a transient mediator
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Using thianthreneS-oxide (TTSO) as a transient mediator,para-arylation and alkenylation of mono-substituted arenes have been demonstratedviaapara-selective thianthrenation/Pd-catalyzed thio-Suzuki-Miyaura coupling sequence under mild conditions. This reaction features a broad substrate scope, and functional group and heterocycle tolerance. The versatility of this approach was further demonstrated by late-stage functionalization of complex bioactive scaffolds, and direct synthesis of some pharmaceuticals, including Tetriprofen, Ibuprofen, Bifonazole, and LJ570.
- Chen, Xiao-Yue,Nie, Xiao-Xue,Wu, Yichen,Wang, Peng
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p. 5058 - 5061
(2020/05/18)
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- Preparation method of para-substituted aryl compound
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The invention discloses a preparation method of a para-substituted aryl compound shown as a formula (I) which is described in the specfication. The preparation method is characterized by comprising the following step of: subjecting an aryl sulfonium salt shown as a formula (II) which is described in the specfication and boride to a coupling reaction in a solvent in an inert atmosphere under the action of alkali and a palladium catalyst to obtain the para-substituted aryl compound. According to the method, mono-substituted aromatic hydrocarbon is taken as a substrate, the aryl sulfonium salt isconstructed in situ, and the palladium catalyst catalyzes the aryl sulfonium salt constructed in situ to undergo the Suzuki-Miyaura coupling reaction, so a mono-substituted aromatic hydrocarbon para-arylation or alkenylation product is constructed quickly and efficiently. The method is mild in conditions, high in substrate universality and wide in tolerance of a heterocyclic coupling substrate.
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- Highly efficient palladium-catalyzed cross-coupling of diarylborinic acids with arenediazoniums for practical diaryl synthesis
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A highly efficient cross-coupling of cost-effective diarylborinic acids with both isolatable and latent arenediazoniums, i.e. tetrafluoroborates and aryltriazenes, respectively, has been developed with a practical palladium catalyst system under base-free conditions in open flask at room temperature. A variety of electronically and sterically various biaryls, in particular, those bearing a coordinative ortho-substituent, could be obtained in good to excellent yields by using 0.3 mol% palladium acetate as catalyst. Features of the protocol including cost-effectiveness of diarylborinic acids, efficacy to heteroatom ortho-substituted substrates and high chemoselectivity to aryl chlorides have been clearly demonstrated in practical synthesis of fungicide Boscalid.
- Wang, Fengze,Wang, Chen,Sun, Guoping,Zou, Gang
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- Direct suzuki-miyaura coupling with naphthalene-1,8-diaminato (dan)-substituted organoborons
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The actually direct Suzuki-Miyaura coupling with "protected" R-B(dan) (dan = naphthalene-1,8-diaminato) was demonstrated to smoothly occur without in situ deprotection of the B(dan) moiety. The use of t-BuOK (Ba(OH)2 in some cases) as a base under anhydrous conditions is the key to the successful cross-coupling, where R-B(dan) is readily converted into a transmetalation-active borate-form, regardless of the well-accepted diminished boron-Lewis acidity.
- Yoshida, Hiroto,Seki, Michinari,Kamio, Shintaro,Tanaka, Hideya,Izumi, Yuki,Li, Jialun,Osaka, Itaru,Abe, Manabu,Andoh, Hiroki,Yajima, Tomoki,Tani, Tomohiro,Tsuchimoto, Teruhisa
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p. 346 - 351
(2019/12/24)
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- Highly active homoleptic nickel(II) bis-N-heterocyclic carbene catalyst for Suzuki–Miyaura and Heck cross-coupling reactions
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New homoleptic nickel(II) biscarbene complex was synthesized and structurally characterized. The complex depicted the excellent catalytic activities with only 3 mol% catalyst loading along with wide substrate scope for the Suzuki–Miyaura cross-coupling reactions (twenty six examples) and Heck coupling reactions (eighteen examples).
- Nirmala, Muthukumaran,Arruri, Sathyanarayana,Vaddamanu, Moulali,Karupnaswamy, Ramesh,Mannarsamy, Maruthupandi,Adinarayana, Mannem,Ganesan, Prabusankar
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supporting information
p. 125 - 134
(2018/11/23)
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- An N-heterocyclic carbene-functionalised covalent organic framework with atomically dispersed palladium for coupling reactions under mild conditions
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Covalent organic frameworks (COFs) are a new class of crystalline porous materials that could function as excellent scaffolds for heterogeneous catalysts. Herein, we report a functionalised COF (COF-NHC) using N-heterocyclic carbene (NHC) as a monomer building block via a facile ionothermal strategy. The simple and easily prepared imine-linked COF-NHC possessed two coordination sites (NHC and amine), which could fix the active component (Pd) tightly in COF, leading to atomically dispersed Pd in a heterogeneous catalyst. The as-prepared Pd@COF-NHC showed high stability in the Suzuki-Miyaura coupling reaction of arylboronic acids and aryl halides in aqueous media at room temperature, and could be easily recycled and reused multiple times without the loss of catalytic activity. Moreover, C-C coupling reactions could be accomplished using triarylbismuth reagents in ethanol aqueous solutions with high yields.
- Yang, Junjuan,Wu, Yuanyuan,Wu, Xiaowei,Liu, Wenjing,Wang, Yaofang,Wang, Junwen
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supporting information
p. 5267 - 5273
(2019/10/11)
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- Salicylaldehyde-stabilized palladium nanoparticles for highly efficient suzuki-miyaura reaction at room temperature
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Pd-catalyzed Suzuki-Miyaura cross-coupling reactions promoted by simple and commercial salicylaldehyde-based ligands were investigated. The effect of the ligands was evaluated and the reaction conditions were optimized. Moreover, the physical nature of the palladium was determined by TEM analysis and poison tests. It demonstrated that this catalytic system can be reused for ten consecutive runs and showed excellent activities toward aryl bromides with arylboronic acids at room temperature in air.
- Zhou, Zhen,Cao, Gao,Liu, Ning
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supporting information
p. 547 - 550
(2019/06/11)
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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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- LiCl-Accelerated Nickel Catalyzed Cross-Coupling of Aryl Tosylates with the Aryl Grignard Reagents
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A mild coupling reaction catalyzed by Ni(acac)2-L4 has been studied. The catalyst acts efficiently in the reaction of biaryl coupling between various electrophiles and common or functionalized aryl Grignard reagents with high functional group tolerance. The study demonstrates that LiCl acts as an essential component in efficient cross-coupling by accelerating reduction of Ni(II) to Ni(0). The new catalytic system for selective couplings of aryl tosylates with aryl chlorides has been developed.
- He, Xiao-Yun,Zhang, Zhi-Xun,Li, Chun-Jing,Li, Yan
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p. 2591 - 2596
(2020/02/25)
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- From agriculture residue to catalyst support; A green and sustainable cellulose-based dip catalyst for C–C coupling and direct arylation
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The core characteristics of a perfect catalyst include good activity, simple design, excellent stability, easy recovery from reaction mixture, recyclability, and have the provision for easy scale up. The ease in synthesis, recyclability and scale up makes the dip catalyst a major contender in this regard which possess most of the aforementioned characteristics. In this work, we report a dip catalyst made of cellulose, isolated from agriculture residue (sugarcane bagasse), in which biogenically synthesized palladium nanoparticles were dispersed. The prepared dip catalyst was characterized by FESEM, EDS, XRD, ATR-IR, TGA, TEM, XPS and ICP-OES analysis. Also, the activity of the dip catalyst was studied in the Suzuki-Miyaura cross-coupling reaction and was found to give excellent conversion with 15 recycles. Further, the activity of dip catalyst in C5-arylation of 2-substituted thiophenes was evaluated for which promising yields were obtained.
- Kandathil, Vishal,Kempasiddaiah, Manjunatha,B. S., Sasidhar,Patil, Siddappa A.
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- Visible-Light-Promoted, Catalyst-Free Gomberg-Bachmann Reaction: Synthesis of Biaryls
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Biaryls were synthesized via a novel visible-light-promoted Gomberg-Bachmann reaction that does not require a photosensitizer or any metal reagents. The formation of an electron donor-acceptor complex between aryl diazonium salts and pyridine allows, under visible-light irradiation, the synthesis of biaryls in moderate-to-high yields.
- Lee, Juyoung,Hong, Boseok,Lee, Anna
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p. 9297 - 9306
(2019/08/12)
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- Anthranilamide (aam)-substituted arylboranes in direct carbon-carbon bond-forming reactions
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Anthranilamide (aam)-substituted arylboranes, which were reported to serve as masked boranes in the Suzuki-Miyaura coupling, have been found to be directly cross-coupled just by use of an aqueous medium. The excellent stability of 2-pyridyl-B(aam) toward protodeborylation allowed their smooth cross-coupling.
- Kamio, Shintaro,Kageyuki, Ikuo,Osaka, Itaru,Yoshida, Hiroto
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supporting information
p. 2624 - 2627
(2019/03/05)
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- CNC pincer palladium complex supported on magnetic chitosan as highly efficient and recyclable nanocatalyst in C─C coupling reactions
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A stable and durable magnetic chitosan-supported triazine-bridged bisimidazolium pincer palladium catalyst (Fe3O4@ChC@CNC-PdII) was synthesized and characterized using various techniques. The Fe3O4@ChC@CNC-PdII complex displayed high activity in the production of substituted biaryls via the cross-coupling reactions of aryl halides with arylboronic acids. Also, this catalyst could be simply recovered from the reaction mixture and reused in 13 consecutive runs with no loss of its catalytic activity.
- Rafiee, Fatemeh,Hosseini, S. Azam
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- Dimeric palladium 1,2,3-triazol-5-ylidene complexes-synthesis, structure, reactivity and catalytic properties in Suzuki coupling
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New dimeric palladium 1,2,3-triazol-5-ylidene complexes of the general formula [{Pd(μ-Cl)Cl(tzNHC)}2] (tzNHC = 1-mesityl-3-methyl-4-phenyl-1H-1,2,3-triazol-5-ylidene; 1-hexyl-3-methyl-4-phenyl-1H-1,2,3-triazol-5-ylidene and 1-butyl-3-methyl-4-phenyl-1H-1,2,3-triazol-5-ylidene) were synthesized and characterized by spectroscopic methods, X-ray analysis and DFT calculations. For the mesityl substituted complex, the crystallographic structures of both the cisoidal and transoidal isomer were obtained. In the presence of an excess of 4-tolylboronic acid, the loss of the tzNHC ligand from the palladium coordination sphere as a 5-tolyltriazolium salt was observed. The complexes are precursors of palladium species catalytically active in the coupling of arylboronic acids with aryl bromides.
- Lorkowski, Jan,Zak, Patrycja,Kubicki, Maciej,Pietraszuk, Cezary,J?drzkiewicz, Dawid,Ejfler, Jolanta
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supporting information
p. 10134 - 10141
(2018/06/18)
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- PEPPSI-type palladium 1,2,3-triazolin-5-ylidene complexes – Synthesis, structure and catalytic properties in Suzuki-Miyaura coupling
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Palladium complexes of the general formula [PdCl2(tzNHC)(pyridine)] bearing a series 1,2,3-triazolin-5-ylidene (tzNHC) ligands were synthesized and characterized by spectroscopic methods and X-ray analysis. Complexes exhibit catalytic activity in the Suzuki-Miyaura coupling of boronic acids with aryl bromides.
- Ostrowska, Sylwia,Kubicki, Maciej,Pietraszuk, Cezary
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supporting information
p. 317 - 323
(2018/06/29)
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- Cyrene as a Bio-Based Solvent for the Suzuki-Miyaura Cross-Coupling
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The Suzuki-Miyaura (SM) cross-coupling is the most broadly utilized Pd-catalyzed C-C bond-forming reaction in the chemical industry. A large proportion of SM couplings employ dipolar aprotic solvents; however, current sustainability initiatives and increasingly stringent regulations advocate the use of alternatives that exhibit more desirable properties. Here we describe the scope and utility of the bio-derived solvent Cyrene in SM cross-couplings and evaluate its suitability as a reaction medium for this benchmark transformation from discovery to gram scale.
- Wilson, Kirsty L.,Murray, Jane,Jamieson, Craig,Watson, Allan J. B.
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supporting information
p. 650 - 654
(2017/12/26)
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- Palladium N-Heterocyclic Carbene Complex of Vitamin B1 Supported on Silica-Coated Fe3O4 Nanoparticles: A Green and Efficient Catalyst for C–C Coupling
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Abstract: Fe3O4@SiO2 nanoparticles were prepared by hydrolysis of TEOS in the presence of Fe3O4 nanoparticles that were synthesized through co-precipitation procedure. Then, thiamine hydrochloride (VB1) was covalently connected with silica to provide a biodegradable, nontoxic and inexpensive NHC ligand for the formation of complex with palladium. This magnetic bionanocatalyst was characterized using FT-IR, XPS, FE-SEM, TEM, EDX, XRD, VSM, TGA and ICP-AES analysis. The Fe3O4@SiO2@VB1-Pd was found as a magnetically separable and highly active catalyst for the Suzuki coupling reactions of various aryl halides with substituted phenylboronic acids. Under appropriate conditions, all reactions afforded the desired products in excellent yields at short reaction times. Moreover, this catalyst can be easily recovered by using a magnetic field and directly reused for five times in this cross coupling with good yield and suitable time. Graphical Abstract: [Figure not available: see fulltext.]
- Rafiee, Fatemeh,Mehdizadeh, Nasrin
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p. 1345 - 1354
(2018/03/28)
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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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- Facile one-pot nanocatalysts encapsulation of palladium-NHC complexes for aqueous Suzuki-Miyaura couplings
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Organic transformations using water as the solvent have been the focus of intense investigation. We herein present a strategy that uses simple nanoparticle encapsulation to fabricate water-soluble nanocatalysts (NCs) for aqueous cross-coupling reactions. To achieve this goal, three types of N-heterocyclic carbene (NHC)-palladium (Pd) complexes (i.e., 1b, 2b, and 3b) with the chemical formula [PdL(CH3CN)Cl]PF6 (where L is a bidentate pyridine- or pyrimidine-bearing NHC ligand) have been synthesized, and their structures were characterized by NMR spectroscopy and X-ray crystallography. Exploiting a facile one-pot encapsulation process, the water-insoluble Pd-NHC complexes can be integrated into the hydrophobic cores of micelles composed of an amphiphilic copolymer. These water-dispersed nanoparticles exhibited excellent catalytic activity in aqueous Suzuki-Miyaura couplings. Among these NCs, 3b-NC, bearing a mesityl moiety on its NHC ligand, was found to be the most active catalyst under the tested reaction conditions. More impressively, 3b-NC can be reused for at least five cycles without substantial loss of catalytic activity.
- Chen, Chao,Zheng, Qing,Ni, Shengliang,Wang, Hangxiang
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p. 4624 - 4630
(2018/03/21)
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- Magnetically recyclable Pd/Fe3O4/g-C3N4 as efficient catalyst for the reduction of nitrophenol and suzuki-miyaura reaction at room temperature
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Herein, we present the design and synthesis of a novel magnetic stable and recyclable catalyst Pd/Fe3O4/g-C3N4 with approachable active palladium nanoparticles (Pd NPs) based on the platelet-like graphitic carbon nitrides (g-C3N4). The Pd NPs, g-C3N4 and magnetic particles (Fe3O4) are tightly connected through non-covalent interactions owing to the layered structure of g-C3N4 with abundant nitrogen atoms, facilitating the stability of Pd/Fe3O4/g-C3N4 and activating the Pd NPs at the same time. The Pd/Fe3O4/g-C3N4 catalyst with a narrow particle size distribution (2.55 nm) of Pd NPs displayed the maintenance of the planar structure of g-C3N4. The activity parameter of the catalyst turned out to be excellent (12.4 s11¢mM11) by fitting the curves derived from the reduction of nitrophenol. Meanwhile, the Suzuki-Miyaura coupling reaction at room temperature processed smoothly with the Pd/Fe3O4/g-C3N4 catalyst. It is meaningful to stress that 2-bromobenzonitrile and p-tolylboronic acid could afford the medical intermediate sartanbiphenyl at total conversion without side reactions in 25 min. Furthermore, the nanocatalyst owes the properties of easy recycling using a powerful magnet as well as high turnover frequency (at least 5 runs) with retention of high catalytic activity.
- Yang, Yingwei,Tang, Ruiren
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p. 544 - 547
(2018/04/09)
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- By the method of preparation synthetize the backward
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The present invention discloses a method for preparing diaromatic hydrocarbon from aromatic hydrazine. The method comprises that: under effects of a bivalent palladium catalyst and camphor sulfonic acid, aryl siloxane and aromatic hydrazine are subjected to a coupling reaction, and after completing the reaction, post-treatment is performed to obtain the diaromatic hydrocarbon. According to the preparation method of the present invention, the specific additive camphor sulfonic acid is added to the reaction system, such that the coupling reaction of the aryl siloxane and the aromatic hydrazine is effectively promoted, the reaction conditions are mild, the self-coupling reaction of the aryl siloxane is inhibited, and the reaction yield is improved.
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Paragraph 0036-0039
(2018/09/26)
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- Copper-catalyzed cross-coupling of aryl-, primary alkyl-, and secondary alkylboranes with heteroaryl bromides
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A method for the Cu-catalyzed cross-coupling of both aryl and alkylboranes with aryl bromides is described. The method employs an inexpensive Cu-catalyst and functions for a variety of heterocyclic as well as electron deficient aryl bromides. In addition, aryl iodides of varying substitution patterns and electronic properties work well.
- Bergmann, Allison M.,Oldham, Adam M.,You, Wei,Brown, M. Kevin
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supporting information
p. 5381 - 5384
(2018/06/01)
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- Integrating Organic Lewis Acid and Redox Catalysis: The Phenalenyl Cation in Dual Role
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In recent years, merging different types of catalysis in a single pot has drawn considerable attention and these catalytic processes have mainly relied upon metals. However, development of a completely metal free approach integrating organic redox and organic Lewis acidic property into a single system has been missing in the current literature. This study establishes that a redox active phenalenyl cation can activate one of the substrates by single electron transfer process while the same can activate the other substrate by a donor-acceptor type interaction using its Lewis acidity. This approach has successfully achieved light and metal-free catalytic C-H functionalization of unactivated arenes at ambient temperature (39 entries, including core moiety of a top-selling molecule boscalid), an economically attractive alternative to the rare metal-based multicatalysts process. A tandem approach involving trapping of reaction intermediates, spectroscopy along with density functional theory calculations unravels the dual role of phenalenyl cation.
- Ahmed, Jasimuddin,Chakraborty, Soumi,Jose, Anex,Sreejyothi,Mandal, Swadhin K.
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supporting information
p. 8330 - 8339
(2018/06/19)
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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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- Radical Arylation of Anilines and Pyrroles via Aryldiazotates
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The radical arylation of anilines and pyrroles can be achieved under transition-metal- and catalyst-free conditions by using aryldiazotates in strongly alkaline aqueous solutions. The aryldiazotates act as protected diazonium ions, which do not undergo azo coupling with electron-rich aromatic substrates, but can still serve as an aryl radical source at slightly elevated temperatures. Based on an improved preparation of aryldiazotates in aqueous solution, homolytic aromatic substitutions of anilines and pyrroles were conducted with good overall yields and high regioselectivity. Moreover, DFT calculations provided further mechanistic insights.
- Hofmann, Josefa,Gans, Eva,Clark, Timothy,Heinrich, Markus R.
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p. 9647 - 9656
(2017/07/22)
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- A phosphine-free, atom-efficient cross-coupling of aryl iodides with triarylindiums or trialkynylindiums catalyzed by immobilization of palladium(0) in MCM-41
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The first phosphine-free heterogeneous atom-efficient cross-coupling reaction of aryl iodides with triarylindiums or trialkynylindiums was achieved in THF at 68 °C by using 1 mol% of MCM-41-immobilized palladium(0)-Schiff base complex [MCM-41-N,N-Pd(0)] as catalyst, yielding a variety of unsymmetrical biaryls and arylalkynes in good to excellent yields. The heterogeneous palladium(0) catalyst could easily be prepared via a simple procedure from commercially readily available reagents, and recovered by filtration of the reaction solution and recycled at least 10 times without significant loss of activity.
- Lei, Zhiwei,Liu, Haiyi,Cai, Mingzhong
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- Amide-ligand-controlled highly para-selective arylation of monosubstituted simple arenes with arylboronic acids
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Pd-catalyzed highly para-selective arylations of monosubstituted simple arenes with arylboronic acids to widely existed biaryls have been developed. Inspired by requisite amide-directing groups in reported selective oxidative couplings, amide ligands, especially DMF, are designed and found to be critical for the selectivity control in current arylations.
- Luan, Yu-Xin,Zhang, Tao,Yao, Wei-Wei,Lu, Ke,Kong, Lu-Yao,Lin, Yu-Tong,Ye, Mengchun
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supporting information
p. 1786 - 1789
(2017/02/15)
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- MCM-41-immobilised nitrogen and sulfur mixed tridentate palladium(0) complex: A highly efficient and recyclable catalyst for the Suzuki reaction of aryl bromides in air
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The novel MCM-41-immobilised nitrogen and sulfur mixed tridentate palladium(0) complex [MCM-41-2N,S-Pd(0)] was prepared from 3-(2-aminoethylamino) propyltrimethoxysilane by immobilisation on MCM-41, followed by reaction with thiophene-2-carboxaldehyde and PdCl2 and then reduction with hydrazine hydrate. This phosphine-free heterogeneous palladium(0) complex was a highly active catalyst for the Suzuki reaction of aryl bromides in air and could be recycled at least 8 times without significant loss of activity.
- Liu, Dayi,Wang, Pingping,Ai, Jingting,Cai, Mingzhong
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p. 186 - 191
(2017/03/24)
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