- trans-Pd(OAc)2(Cy2NH)2 catalyzed Suzuki coupling reactions and its temperature-dependent activities toward aryl bromides
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A new catalytic system based on Pd-simple amines for Suzuki coupling reactions of aryl bromides is described. A well-defined air-stable complex, trans-Pd(OAc)2(Cy2NH)2 effectively promotes Suzuki couplings of aryl bromides with a range of aryl boronic acids to give diaryl products in high yields. It also exhibits temperature-dependent activity toward aryl bromides bearing different electronic substituents under reaction conditions.
- Tao, Bin,Boykin, David W.
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- Magnetic nanoparticles supported N-heterocyclic palladium complex: Synthesis and catalytic evaluations in Suzuki cross-coupling reaction
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Because of the robustness and magnetic properties, the magnetic materials are promising and alternative candidate for the fabrication of noble metal in chemical catalysis from the viewpoint of green chemistry. Accordingly, an eco-friendly magnetic palladium catalyst loaded on N-Methylimidazole functionalized Fe3O4@SiO2 nanoparticles (Fe3O4@SiO2-NMIM-Pd) has been designed and prepared in the present work. The resultant composite exhibited excellent catalytic activity towards the Suzuki cross-coupling reaction for the synthesis of the corresponding biaryls in good to excellent yields (up to 96%) under aerobic conditions. In particular, this catalyst could be easily recovered through magnetic separation in a few cycles. The as-prepared palladium complex showed advantages including high thermal stability, low toxicity, moisture and oxygen insensitivities in Suzuki reactions. More importantly, this study presents a catalysis system, which will provide the magnetic materials access to the potential applications in a wide range of green organic catalysis.
- Dong, Yahao,Xue, Fengjun,Wei, Yuping
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- Suzuki–Miyaura Coupling of (Hetero)Aryl Sulfones: Complementary Reactivity Enables Iterative Polyaryl Synthesis
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Ideal organic syntheses involve the rapid construction of C?C bonds, with minimal use of functional group interconversions. The Suzuki–Miyaura cross-coupling (SMC) is a powerful way to form biaryl linkages, but the relatively similar reactivity of electrophilic partners makes iterative syntheses involving more than two sequential coupling events difficult to achieve without additional manipulations. Here we introduce (hetero)aryl sulfones as electrophilic coupling partners for the SMC reaction, which display an intermediate reactivity between those of typical aryl (pseudo)halides and nitroarenes. The new complementary reactivity allows for rapid sequential cross-coupling of arenes bearing chloride, sulfone and nitro leaving groups, affording non-symmetric ter- and quateraryls in only 2 or 3 steps, respectively. The SMC reactivity of (hetero)aryl sulfones is demonstrated in over 30 examples. Mechanistic experiments and DFT calculations are consistent with oxidative addition into the sulfone C?S bond as the turnover-limiting step. The further development of electrophilic cross-coupling partners with complementary reactivity may open new possibilities for divergent iterative synthesis starting from small pools of polyfunctionalized arenes.
- Chatelain, Paul,Sau, Abhijit,Rowley, Christopher N.,Moran, Joseph
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supporting information
p. 14959 - 14963
(2019/11/05)
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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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- N-Methylimidazole functionalized carboxymethycellulose-supported Pd catalyst and its applications in Suzuki cross-coupling reaction
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In this paper, N-Methylimidazole functionalized carboxymethylcellulose-supported palladium nanoparticles (CMC-NHC-Pd) was synthesized and characterized by TEM, SEM, EDX, CP/MAS 13C NMR, FT-IR, TGA, XRD, and XPS analysis. The prepared nanoparticles can be used as an environmentally-friendly and trifunctional catalyst. The well-designed CMC supported palladium nanoparticles catalyst with polydentate ligands is also stable and efficient for Suzuki cross-coupling reactions under mild conditions through the cooperative interaction of trifunctional capturing sites with palladium, ?COO?, ?OH and N-Methylimidazole. This catalyst can be readily recovered by a few cycles of simple filtration. This work proposes a plausible trifunctional catalyst complex.
- Dong, Yahao,Wu, Xiaotian,Chen, Xiaofeng,Wei, Yuping
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p. 106 - 114
(2017/01/03)
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- Maghemite decorated with ultra-small palladium nanoparticles (γ-Fe2O3-Pd): Applications in the Heck-Mizoroki olefination, Suzuki reaction and allylic oxidation of alkenes
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A nanocatalyst comprising ultra-small Pd/PdO nanoparticles (57Fe M?ssbauer spectroscopy. The cost-effective catalyst could be easily separated from the reaction mixture by using an external magnet and reused four times without any loss of activity; chemical stability and recyclability aspects of the catalyst were investigated.
- Rathi, Anuj K.,Gawande, Manoj B.,Pechousek, Jiri,Tucek, Jiri,Aparicio, Claudia,Petr, Martin,Tomanec, Ondrej,Krikavova, Radka,Travnicek, Zdenek,Varma, Rajender S.,Zboril, Radek
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p. 2363 - 2373
(2016/05/19)
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- Catalytic Decarboxylative Cross-Coupling of Aryl Chlorides and Benzoates without Activating ortho Substituents
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The restriction of decarboxylative cross-coupling reactions to ortho-substituted or heterocyclic carboxylate substrates was overcome by holistic optimization of a bimetallic Cu/Pd catalyst system. The combination of a CuI/Me4phen decarboxylation catalyst and a [(MeCN)4Pd](OTf)2/XPhos cross-coupling catalyst enables the synthesis of biaryls from inexpensive aryl chlorides and potassium benzoates regardless of their substitution pattern. Lifting the restriction: A combination of a CuI/Me4phen decarboxylation catalyst and a [(MeCN)4Pd](OTf)2/XPhos cross-coupling catalyst enables the synthesis of biaryls from inexpensive aryl chlorides and potassium benzoates regardless of their substitution pattern (see scheme; FG=functional group). This approach lifts the restriction of decarboxylative cross-coupling reactions to ortho-substituted or heterocyclic carboxylate substrates.
- Tang, Jie,Biafora, Agostino,Goossen, Lukas J.
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supporting information
p. 13130 - 13133
(2015/11/02)
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- Palladium nanoparticles on noncovalently functionalized graphene-based heterogeneous catalyst for the Suzuki-Miyaura and Heck-Mizoroki reactions in water
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We describe here a methodology to synthesize a reusable heterogeneous catalyst based on palladium nanoparticles (Pd NPs) supported on noncovalently functionalized graphene using 1-pyrene carboxylic acid. This can be used efficiently for Suzuki-Miyaura and Heck-Mizoroki reactions in water up to five cycles, providing excellent yields with high selectivity of cross coupled products. It is also useful for more challenging substrates like electron-rich and electron-poor bromoarenes and chloroarenes which resulted in good isolated yields (alkenes and biphenyls) in pure water. Use of functionalized graphene in the catalyst preparation improved the dispersion of it in water medium and also acted as a stabilizing agent for the Pd NPs. The percentage of metal loading in the catalyst and its thermal stability were determined by inductively coupled plasma atomic emission spectroscopy and thermo gravimetric analysis respectively. The composite formation was confirmed by X-ray diffraction patterns, Fourier transform infrared spectroscopy and Raman spectroscopy. The surface elemental composition with oxidation state was determined by UV-visible and X-ray photoelectron spectroscopy. The size and morphology of the Pd NPs on the functionalized graphene sheets were directly observed by Transmission Electron Microscopy.
- Sharavath, Vittal,Ghosh, Sutapa
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p. 48322 - 48330
(2014/12/10)
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- Peptide nanofibers decorated with Pd nanoparticles to enhance the catalytic activity for C-C coupling reactions in aerobic conditions
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We report the synergistic effects of peptide nanofibers decorated with Pd nanoparticles to enhance the catalytic activity for C-C coupling reactions in mild and aerobic conditions.
- Maity, Indrajit,Rasale, Dnyaneshwar B.,Das, Apurba K.
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p. 2984 - 2988
(2014/01/06)
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- Air-stable Pd(II) catalysts with cryptand-22 ligand for convenient and?efficient Suzuki cross-coupling reactions
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Air-stable Pd(II) catalysts with cryptand-22 ligand was easily handled in atm air at room temperature for Suzuki cross-coupling reactions of aryl bromides with arylboronic acids both containing electron-withdrawing and electron-donating groups. Generally, reactions proceeded fast to completion in 2 h to give high product yields. Our Pd(OAc)2/cryptand-22 catalyst is unique, since the reaction solution remained yellow during reaction period and air-stable without formation of Pd black as usually observed for ordinary simple amine ligands.
- Hsu, Ming-Hui,Hsu, Chien-Ming,Wang, Ju-Chun,Sun, Chia-Hsing
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p. 4268 - 4274
(2008/09/20)
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- Suzuki-Miyaura coupling reaction of aryl chlorides using di(2,6-dimethylmorpholino)phenylphosphine as ligand
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Suzuki-Miyaura coupling was achieved on a variety of aryl chlorides by using di(2,6-dimethylmorpholino)phenylphosphine (L1) as a bulky electron-rich monoaryl phosphine ligand. We report the couplings of various chlorobenzenes and heteroaryl chlorides.
- Cho, Su-Dong,Kim, Ho-Kyun,Yim, Heung-seop,Kim, Mi-Ra,Lee, Jin-Kook,Kim, Jeum-Jong,Yoon, Yong-Jin
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p. 1345 - 1352
(2007/10/03)
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- Microwave-assisted Suzuki coupling reactions with an encapsulated palladium catalyst for batch and continuous-flow transformations
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This article describes the design, optimisation and development of a Suzuki cross-coupling protocol mediated by an efficient palladium-en-capsulated catalyst (Pd EnCat) under microwave irradiation. The methodology has been used in both batch mode for classical library preparation and in continuous-flow applications furnishing multigram quantities of material. Described is a method that uses direct focused microwave heating whilst applying an external cooling source. This enables a lower than normal bulk temperature to be maintained throughout the reaction period leading to significant improvements in the overall yield and purity of the reaction products. Additional aspects of this novel heating protocol are discussed in relation to the prolonged lifetime and enhanced reactivity of the immobilised catalyst system.
- Baxendale, Ian R.,Griffiths-Jones, Charlotte M.,Ley, Steven V.,Tranmer, Geoffrey K.
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p. 4407 - 4416
(2008/02/07)
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- Simple amine/Pd(OAc)2-catalyzed Suzuki coupling reactions of aryl bromides under mild aerobic conditions
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A new palladium catalyst (DAPCy) made from Pd(OAc)2 and commercially available, inexpensive dicyclohexylamine has been developed for the Suzuki coupling reaction of aryl bromides with boronic acids to give the coupling products in good to high yields. The air-stable catalyst was characterized and well-defined by X-ray crystallography. A catalytic system involving DAPCy in dioxane demonstrates a temperature-dependent reactivity toward aryl bromides with different electronic substituents, and selectively couples electron-deficient aryl bromides with boronic acids over electron-rich ones at room temperature. Another catalytic system employing DAPCy in EtOH provides a general and convenient method to prepare biaryls from aryl bromides and boronic acids with a broad range of functional groups at room temperature and under aerobic conditions.
- Tao, Bin,Boykin, David W.
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p. 4330 - 4335
(2007/10/03)
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- Palladium-catalyzed Suzuki-Miyaura cross-coupling reactions of potassium aryl- and heteroaryltrifluoroborates
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An extended study of the reactivity of potassium aryl- and heteroaryltrifluoroborates in Suzuki-Miyaura cross-coupling reactions is presented. The coupling of aryl- and electron-rich heteroaryltrifluoroborates with aryl and activated heteroaryl bromides proceeds readily under ligandless conditions. When deactivated aryl- and heteroaryltrifluoroborates are coupled with aryl and heteroaryl bromides and chlorides, a low loading (0.5-2%) of PdCl2(dppf)·CH2Cl2 efficiently catalyzes the reactions. Under either condition, reactions can generally be carried out in an open atmosphere.
- Molander, Gary A.,Biolatto, Betina
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p. 4302 - 4314
(2007/10/03)
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- Cyclic imino derivatives and pharmaceutical compositions containing them
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The invention relates to cyclic imino compounds which have, inter alia, valuable pharmacological properties, especially inhibitory effects on cell aggregation, pharmaceutical compositions which contain these compounds and processes for preparing them.
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