- Heck reactions in aqueous miniemulsions
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Carrying out organic reactions in water-based nanoreactors represents a 'green' method for the preparation of organic compounds. This process eliminates the need for solvents, thus reducing the effect of high volumes of solvent on the environment. In this work, we demonstrate a successful Heck cross-coupling reaction, one of the most used approaches to form CC bonds using a palladium catalyst, in a miniemulsion. The miniemulsion droplet sizes were small (25 to 42nm), and the reactions resulted in high conversions of three different products with high trans stereoisomers.
- Zayas, Hazit A.,Valade, David,Jia, Zhongfan,Monteiro, Michael J.
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- “TPG-lite”: A new, simplified “designer” surfactant for general use in synthesis under micellar catalysis conditions in recyclable water
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Using the oxidized, carboxylic acid-containing form of MPEG-750, esterification with racemic vitamin E affords a new surfactant (TPG-lite) that functions as an enabling, nanoreactor-forming amphiphile for use in many types of important reactions in synthesis. The presence of a single ester bond is suggestive of simplified treatment as a component of (eventual) reaction waste water, after recycling. Many types of reactions, including aminations, Suzuki-Miyaura, SNAr, and several others are compared directly with TPGS-750-M, leading to the conclusion that TPG-lite can function as an equivalent nanomicelle-forming surfactant in water. Prima facie evidence amassed via DLS and cryo-TEM analyses support these experimental observations. In silico evaluations of the aquatic toxicity and carcinogenicity of TPG-lite indicate that it is safe to use.
- Thakore, Ruchita R.,Takale, Balaram S.,Hu, Yuting,Ramer, Selene,Kostal, Jakub,Gallou, Fabrice,Lipshutz, Bruce H.
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- Selective Construction of C?C and C=C Bonds by Manganese Catalyzed Coupling of Alcohols with Phosphorus Ylides
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Herein, we report the manganese catalyzed coupling of alcohols with phosphorus ylides. The selectivity in the coupling of primary alcohols with phosphorus ylides to form carbon-carbon single (C?C) and carbon-carbon double (C=C) bonds can be controlled by the ligands. In the conversion of more challenging secondary alcohols with phosphorus ylides the selectivity towards the formation of C?C vs. C=C bonds can be controlled by the reaction conditions, namely the amount of base. The scope and limitations of the coupling reactions were thoroughly evaluated by the conversion of 21 alcohols and 15 ylides. Notably, compared to existing methods, which are based on precious metal complexes as catalysts, the present catalytic system is based on earth abundant manganese catalysts. The reaction can also be performed in a sequential one-pot reaction generating the phosphorus ylide in situ followed manganese catalyzed C?C and C=C bond formation. Mechanistic studies suggest that the C?C bond was generated via a borrowing hydrogen pathway and the C=C bond formation followed an acceptorless dehydrogenative coupling pathway. (Figure presented.).
- Liu, Xin,Werner, Thomas
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supporting information
p. 1096 - 1104
(2020/12/31)
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- Non-Chelate-Assisted Palladium-Catalyzed Aerobic Oxidative Heck Reaction of Fluorobenzenes and Other Arenes: When Does the C?H Activation Need Help?
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The pyridone fragment in the ligand [2, 2’-bipyridin]-6(1H)-one (bipy-6-OH) enables the oxidative Heck reaction of simple arenes with oxygen as the sole oxidant and no redox mediator. Arenes with either electron-donating or electron-withdrawing groups can be functionalized in this way. Experimental data on the reaction with toluene as the model arene shows that the C?H activation step is turnover limiting and that the ligand structure is crucial to facilitate the reaction, which supports the involvement of the pyridone fragment in the C?H activation step. In the case of fluoroarenes, the alkenylation of mono and 1,2-difluoro benzenes requires the presence of bipy-6-OH. In contrast, this ligand is detrimental for the alkenylation of 1,3-difluoro, tri, tetra and pentafluoro benzenes which can be carried out using just [Pd(OAc)2]. This correlates with the acidity of the fluoroarenes, the most acidic undergoing easier C?H activation so other steps of the reaction such as the coordination-insertion of the olefin become kinetically important for polyfluorinated arenes. The use of just a catalytic amount of sodium molybdate as a base proved to be optimal in all these reactions. (Figure presented.).
- Albéniz, Ana C.,Villalba, Francisco
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supporting information
p. 4795 - 4804
(2021/09/06)
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- Alkene Synthesis by Photo-Wolff-Kischner Reaction of Sulfur Ylides and N-Tosylhydrazones
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A visible-light-driven and room temperature photo-Wolff-Kischner reaction of sulfur ylides and N-tosylhydrazones has been developed for the first time to provide modular access to alkene synthesis. The high functional group tolerance and broad substrate scope were demonstrated by more than 60 examples. Both E- and Z-olefinic stereochemistry in the products could be controlled with excellent stereoselectivity. A series of mechanistic studies support that the reaction should proceed through a radical-carbanion crossover pathway, specifically involving addition of photo-generated sulfur ylide radical cations to N-tosylhydrazones to form carbanions and subsequent Wolff-Kischner process.
- Gao, Pan-Pan,Yan, Dong-Mei,Bi, Ming-Hang,Jiang, Min,Xiao, Wen-Jing,Chen, Jia-Rong
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p. 14195 - 14201
(2021/09/20)
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- Water-Sculpting of a Heterogeneous Nanoparticle Precatalyst for Mizoroki-Heck Couplings under Aqueous Micellar Catalysis Conditions
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Powdery, spherical nanoparticles (NPs) containing ppm levels of palladium ligated by t-Bu3P, derived from FeCl3, upon simple exposure to water undergo a remarkable alteration in their morphology leading to nanorods that catalyze Mizoroki-Heck (MH) couplings. Such NP alteration is general, shown to occur with three unrelated phosphine ligand-containing NPs. Each catalyst has been studied using X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and cryogenic transmission electron microscopy (cryo-TEM) analyses. Couplings that rely specifically on NPs containing t-Bu3P-ligated Pd occur under aqueous micellar catalysis conditions between room temperature and 45 °C, and show broad substrate scope. Other key features associated with this new technology include low residual Pd in the product, recycling of the aqueous reaction medium, and an associated low E Factor. Synthesis of the precursor to galipinine, a member of the Hancock family of alkaloids, is suggestive of potential industrial applications.
- Pang, Haobo,Hu, Yuting,Yu, Julie,Gallou, Fabrice,Lipshutz, Bruce H.
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supporting information
p. 3373 - 3382
(2021/04/07)
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- Gelatin-pyrolyzed mesoporous N-doped carbon supported Pd as high-performance catalysts for aqueous Heck reactions
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Nitrogen-doped mesoporous carbon-supported Pd (Pd@N-C) catalysts were prepared by pyrolyzing gelatin/templates/PdCl2 hydrogels under N2 atmosphere at 800°C. Using poly (ethylene glycol) block poly (propylene glycol) block poly (ethyl
- Yang, Shuai,Chen, Yuli,Huang, Shuaijian,Deng, Lu,Wu, Yuanyuan,Zheng, Xiu,Omonov, Shakhzodjon,Zeng, Minfeng
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- Highly effective cellulose supported 2-aminopyridine palladium complex (Pd(II)-AMP-Cell?Al2O3) for Suzuki-Miyaura and Mizoroki–Heck cross-coupling
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In the present work, a novel, highly efficient, retrievable organo–inorganic hybrid heterogeneous catalyst (Pd(II)-AMP-Cell?Al2O3) has been prepared by covalent grafting of 2-aminopyridine on chloropropyl modified cellulose-alumina composite followed by complexation with palladium acetate. The catalyst was characterized by techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), inductive coupled plasma-atomic emission spectroscopy (ICP-AES) and thermo gravimetric analysis (TGA). The catalyst has been successfully employed in Suzuki-Miyaura as well as Mizoroki–Heck cross-coupling reactions. The reactions proceed smoothly resulting in the high yields of cross-coupling products (81 to 95%) within short reaction times. The catalyst can be efficiently recovered by simple filtration and reused for multiple cycles without considerable loss in the catalytic activity. The key-features of the present protocol include mild reaction conditions, simple work-up procedure, high stability of the catalyst, high turnover number (TON) and frequency (TOF), ease recovery and reusability of the catalyst.
- Mhaldar, Pradeep,Pore, Dattaprasad,Rashinkar, Gajanan,Vibhute, Sandip
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- Mono- and dinuclear palladium(II) complexes incorporating 1,2,3-triazole-derived mesoionic carbenes: syntheses, solid-state structures and catalytic applications
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Two 1,2,3-triazole-derived monocationic salts 3 and 4 bearing N-aryl wingtips were prepared using copper-catalyzed “click” reactions followed by alkylations with iodomethane. Employing a silver–carbene transfer method, two dinuclear palladium(II) complexes of triazolin-5-ylidenes (5/6) were obtained, the former of which has been reported previously. Bridge-cleavage reaction of 5 as a representative with PPh3 yielded cis-configured mesoionic carbene/phosphine hybrid complex cis-7 and homoleptic bis(phosphine) complex 8, suggesting the presence of a ligand exchange process. In contrast, bridge breakages of 5/6 with pyridine cleanly afforded PEPPSI-type complexes 9 and 10 in near quantitative yields. Finally, all complexes were exploited to catalyze Mizoroki–Heck coupling reactions with aryl bromides as the substrates, and PEPPSI-type complex 9 was found to be the best performer generally giving good to excellent yields.
- Zhang, Xin,Yan, Xuechao,Zhang, Bo,Wang, Ran,Guo, Shuai,Peng, Shiyong
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- Mizoroki–Heck Cross-Coupling of Acrylate Derivatives with Aryl Halides Catalyzed by Palladate Pre-Catalysts
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The Mizoroki–Heck (MH) reaction involving aryl halides with various acrylates and acrylamides has been studied using air and moisture-stable imidazolium-based palladate pre-catalysts. These pre-catalysts can be converted into Pd-NHC species (NHC = N-heterocyclic carbene) under catalytic conditions and are capable of facilitating the Mizoroki–Heck reaction of aryl halides with various acrylates. The effects of solvent, catalyst loading, temperature and bases on the reaction outcome have been investigated. Various coupling partners were tolerated under the optimal reaction conditions catalyzed by palladate 1, [SIPr·H][Pd(η3-2-Me-allyl)Cl2]. The efficiency of the optimized synthetic methodology was tested on various aryl halides and substituted acrylates as well as acrylamides. The MH reaction yielded the coupled products in good to excellent isolated yields (up to 98%).
- Islam, Mohammad Shahidul,Nahra, Fady,Tzouras, Nikolaos V.,Barakat, Assem,Cazin, Catherine S. J,Nolan, Steven P.,Al-Majid, Abdullah Mohammed
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supporting information
p. 4695 - 4699
(2019/11/13)
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- A polymer-supported salen-palladium complex as a heterogeneous catalyst for the Mizoroki-Heck cross-coupling reaction
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In this work, the catalytic performance of a polymer-supported Pd(II)-salen complex (PS-Pd-salen) as an effective and environmentally friendly catalyst for the Mizoroki-Heck C[sbnd]C cross-coupling reaction is presented. The PS-Pd-salen complex was employed as a catalyst for Mizoroki-Heck reactions of an aryl halide with various terminal alkenes (Styrene, Methyl acrylate, Ethyl acrylate, n-butyl acrylate, tert-Butyl acrylate) under phosphine free conditions. Moreover, a range of Mizoroki-Heck reactions using different polar solvents, co-solvents, and bases has been investigated. Aryl iodides and bromides with terminal alkene are well activated in C[sbnd]C coupling reactions. All products were isolated by column chromatography as liquids/white to off-white crystalline solids and confirmed by 1H and 13C NMR spectroscopy. The catalyst could be easily separated by filtrations and reusability of catalyst was also assessed under optimized conditions. The hot filtration test revealed that the catalyst was truly heterogeneous, very active and stable under the reaction conditions and could be reused up to fifth cycles with analogous activities to that of the fresh catalyst. High catalytic activity at a low concentration (30 mg) and flexibility under mild reaction conditions, simple product work-up towards Mizoroki-Heck reactions indicated that PS-Pd-salen was an efficient catalyst for C[sbnd]C coupling reactions.
- Balinge, Kamlesh Rudreshwar,Bhagat, Pundlik Rambhau
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- Probing the Evolution of Palladium Species in Pd@MOF Catalysts during the Heck Coupling Reaction: An Operando X-ray Absorption Spectroscopy Study
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The mechanism of the Heck C-C coupling reaction catalyzed by Pd@MOFs has been investigated using operando X-ray absorption spectroscopy (XAS) and powder X-ray diffraction (PXRD) combined with transmission electron microscopy (TEM) analysis and nuclear magnetic resonance (1H NMR) kinetic studies. A custom-made reaction cell was used, allowing operando PXRD and XAS data collection using high-energy synchrotron radiation. By analyzing the XAS data in combination with ex situ studies, the evolution of the palladium species is followed from the as-synthesized to its deactivated form. An adaptive reaction mechanism is proposed. Mononuclear Pd(II) complexes are found to be the dominant active species at the beginning of the reaction, which then gradually transform into Pd nanoclusters with 13-20 Pd atoms on average in later catalytic turnovers. Consumption of available reagent and substrate leads to coordination of Cl- ions to their surfaces, which causes the poisoning of the active sites. By understanding the deactivation process, it was possible to tune the reaction conditions and prolong the lifetime of the catalyst.
- Yuan, Ning,Pascanu, Vlad,Huang, Zhehao,Valiente, Alejandro,Heidenreich, Niclas,Leubner, Sebastian,Inge, A. Ken,Gaar, Jakob,Stock, Norbert,Persson, Ingmar,Martín-Matute, Belén,Zou, Xiaodong
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supporting information
p. 8206 - 8217
(2018/06/22)
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- Fabrication of Pd/CuFe2O4 hybrid nanowires: A heterogeneous catalyst for Heck couplings
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The development of environmentally benign transformations is indispensable in organic synthesis. Herein, a hybrid heterogeneous catalyst, palladium(0) on copper ferrite nanowires, has been synthesized, characterized, and for the first time, employed in the Jeffrey Heck reaction between iodoarenes and allylic alcohols, and good to excellent yields have been obtained. In addition, the catalyst was found to be suitable for the usual Heck coupling. The nanocatalyst was recovered and reused up-to multiple runs without any noticeable loss of its catalytic activity.
- Lakshminarayana,Mahendar,Ghosal,Sreedhar,Satyanarayana,Subrahmanyam, Ch.
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p. 1646 - 1654
(2018/02/09)
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- Monodentate phosphorus-coordinated palladium(II) complexes as new catalyst for Mizoroki-Heck reaction of aryl halides with electron-deficient olefins
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Four novel palladium(II) complexes coordinated by phosphorus atoms from both 3,5-disubstituted-1H-1,2,4-diazaphospholes in monodentate fashion were developed as efficient catalyst for the Mizoroki-Heck reaction of aryl halides with electron-deficient olefins. The coupling reaction of aryl halide bearig different functional groups with olefin derivatives took place and the corresponding products were isolated in good to excellent yields under optimal conditions. The procedure exhibits good functional group tolerance and wide substrate scope. This Mizoroki-Heck reaction was further achieved using Pd(OAc)2 and 3,5-di-isopropyl-1H-1,2,4-diazaphospholes as combined catalyst, which provide the convenient and alternative method in organic synthesis
- Zhao, Fang,Xin, Li,Zhang, Yingying,Jia, Xuefeng
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supporting information
p. 493 - 496
(2017/09/06)
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- Bioactivity and structure-activity relationship of cinnamic acid esters and their derivatives as potential antifungal agents for plant protection
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A series of cinnamic acid esters and their derivatives were synthesized and evaluated for antifungal activities in vitro against four plant pathogenic fungi by using the mycelium growth rate method. Structure-activity relationship was derived also. Almost all of the compounds showed some inhibition activity on each of the fungi at 0.5 mM. Eight compounds showed the higher average activity with average EC50 values of 17.4-28.6 μg/mL for the fungi than kresoxim-methyl, a commercial fungicide standard, and ten compounds were much more active than commercial fungicide standards carbendazim against P. grisea or kresoxim-methyl against both P. grisea and Valsa Mali. Compounds C1 and C2 showed the higher activity with average EC50 values of 17.4 and 18.5 μg/mL and great potential for development of new plant antifungal agents. The structure-activity relationship analysis showed that both the substitution pattern of the phenyl ring and the alkyl group in the alcohol moiety significantly influences the activity. There exists complexly comprehensive effect between the substituents on the phenyl ring and the alkyl group in the alcohol moiety on the activity. Thus, cinnamic acid esters showed great potential the development of new antifungal agents for plant protection due to high activity, natural compounds or natural compound framework, simple structure, easy preparation, low-cost and environmentally friendly.
- Zhou, Kun,Chen, Dongdong,Li, Bin,Zhang, Bingyu,Miao, Fang,Zhou, Le
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- Self-assembled Pd nanoparticle-containing ionic liquid: Efficient and reusable catalyst for the Heck reaction in water
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A self-assembled Pd nanoparticle-containing ionic liquid as metal–organic polymer was successfully prepared. The structure of the catalyst was characterized using Fourier transform infrared and 1H NMR spectroscopies, scanning electron microscopy and elemental analysis. The catalyst was effectively employed in the palladium-catalyzed Heck reaction in water as a green solvent. Moreover, due to its stability the catalyst can be recovered simply and effectively and reused nine times without much loss of activity.
- Zong, Yingxiao,Wang, Junke,An, Pengli,Yue, Guoren,Pan, Yi,Wang, Xicun
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p. 2389 - 2396
(2017/09/30)
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- RETRACTED ARTICLE: A Recycling-Free Nanocatalyst System: The Stabilization of in Situ-Reduced Noble Metal Nanoparticles on Silicone Nanofilaments via a Mussel-Inspired Approach
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The recovery and reuse of costly nanocatalysts is an essential operation in modern nanocatalysis, and improvements in catalyst reusability can contribute significantly to the economic viability and sustainable development of nanocatalysis. Herein, starting with the application of a silicone nanofilament (SNF) coating on a target substrate, a mussel-inspired approach in the form of polydopamine (PDA) deposition on the SNF surface was used to form in situ-reduced Pd nanoparticles (Pd NPs) and to stabilize them on the SNFs. This PDA-mediated approach enabled a high integrity nanocatalyst system to be built on a free-standing SNF support while retaining the porosity in the original SNF architecture. The SNFs-Pd nanocomposites prepared as such were applied to the inside walls of laboratory chemical reactors and used as recycling-free nanocatalyst systems for Pd-catalyzed organic reactions without the laborious conventional catalyst recovery and redispersion processes. The SNFs-Pd catalyst system exhibited high activity and high selectivity in single and successive Heck coupling reactions; and a reusability as high as 90% was still possible in the 20th cycle. This mussel-inspired approach is highly versatile and can be applied to laboratory chemical reactors in different shapes, sizes, and configurations to scale up the nanocatalyst applications. Furthermore, the general utility of the chemistry involved allows this surface modification technique to apply to other supported noble metal (e.g., Ag, Au, and Pt) catalysts, thereby increasing the usability and the performance of nanocatalyst systems.
- Fei, Xiang,Kong, Wangqing,Chen, Xin,Jiang, Xuejiao,Shao, Zhengzhong,Lee, Jim Yang
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p. 2412 - 2418
(2017/06/01)
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- Methionine-functionalized chitosan–Pd(0) complex: A novel magnetically separable catalyst for Heck reaction of aryl iodides and aryl bromides at room temperature in water as only solvent
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We report a novel catalyst system with an immobilized palladium metal-containing magnetic nanoparticle core (ImmPd(0)-MNPs) for the Heck reaction. ImmPd(0)-MNPs was found to be an exceptionally mild and versatile catalyst for the Heck reaction of aryl iodides and bromides at room temperature. The catalyst was simply recovered using an external magnet from the reaction mixture and recycled six times. The results showed that the catalyst was very active and stable. Moreover, the reaction was carried out in water as a green and environmentally acceptable solvent. In terms of scope and mildness, ImmPd(0)-MNPs is an improvement over previously reported catalysts for Heck coupling methods.
- Hajipour, Abdol R.,Tavangar-Rizi, Zeinab
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- Synthesis and characterization of N-heterocyclic carbene–PdCl2–1H-benzotriazole complexes and their catalytic activities toward Mizoroki–Heck and Sonogashira reactions
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Four heteroleptic palladium complexes containing both N-heterocyclic carbenes and 1H-benzotriazole were synthesized and characterized. The solid-state structures show mononuclear carbene palladium complexes with each palladium coordinated by an NHC, the 3-position nitrogen of 1H-benzotriazole and two trans chlorides. The catalytic performance of the complexes for Mizoroki–Heck and Sonogashira reactions were further investigated. The results reveal that the complexes show high catalytic activities for coupling of aryl bromides with alkenes and alkynes.
- Yang, Jin
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p. 441 - 450
(2017/01/28)
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- Pd and Ni complexes of a novel vinylidene β-diketimine ligand: Their application as catalysts in Heck coupling and alkyne trimerization
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A β-diketimine ligand with vinylidene substitution at γ-carbon, CH2C(CH3CNAr)2 (Ar?=?2,6-diisopropylphenyl) (L2), was synthesized by treating β-diketimine H2C(CH3CNAr)2 with n-BuLi followed by paraformaldehyde. L2 formed the homobimetallic ether-bridged β-diketiminate complex [O{(CH2-β-diketiminate)Pd(OAc)}2] (1) with (PdOAc)2. It also gave complexes [L2PdCl2] (2) and [L2NiBr2] (3) when treated with PdCl2(CH3CN)2 and NiBr2(dimethoxyethane), respectively. All the compounds were characterized using 1H/13C NMR spectroscopy and single-crystal X-ray diffraction studies. The catalytic activity of Pd and Ni complexes 1, 2 and 3 was explored in Heck coupling and alkyne trimerization reactions and it was found that they are very good catalysts. The results are reported in detail.
- Beesam, Raghavendra,Nareddula, Dastagiri Reddy
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- Total Synthesis and Biological Assessment of Novel Albicidins Discovered by Mass Spectrometric Networking
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Natural products represent an important source of potential novel antimicrobial drug leads. Low production by microorganisms in cell culture often delays the structural elucidation or even prevents a timely discovery. Starting from the anti-Gram-negative antibacterial compound albicidin produced by Xanthomonas albilineans, we describe a bioactivity-guided approach combined with non-targeted tandem mass spectrometry and spectral (molecular) networking for the discovery of novel antimicrobial compounds. We report eight new natural albicidin derivatives, four of which bear a β-methoxy cyanoalanine or β-methoxy asparagine as the central α-amino acid. We present the total synthesis of these albicidins, which facilitated the unambiguous determination of the (2 S,3 R)-stereoconfiguration which is complemented by the assessment of the stereochemistry on antibacterial activity.
- von Eckardstein, Leonard,Petras, Daniel,Dang, Tam,Cociancich, Stéphane,Sabri, Souhir,Gr?tz, Stefan,Kerwat, Dennis,Seidel, Maria,Pesic, Alexander,Dorrestein, Pieter C.,Royer, Monique,Weston, John B.,Süssmuth, Roderich D.
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supporting information
p. 15316 - 15321
(2017/10/20)
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- An efficient palladium catalyzed Mizoroki-Heck cross-coupling in water
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The homogeneous Pd-catalysed Mizoroki-Heck coupling reaction was successfully performed in water in the absence of any additives under aerobic conditions. The various key reaction parameters that affect the yield of the desired cross-coupling product were optimized. The Pd(PPh3)4/Et3N/H2O/98 °C catalyst system was found to be highly active (TOF = 12 to 14 h-1) towards achieving excellent yield of the Mizoroki-Heck coupling products for a wide range of electron-withdrawing as well as electron-donating aryl bromides and chlorides in the shortest reaction time. Pd(PPh3)4 catalyst deactivation during the Mizoroki-Heck coupling reaction was investigated and to evolve a strategy for achieving ten times Pd-metal recyclability without appreciable loss of its activity. Thus, the proposed mechanism provides access to a variety of olefins in aqueous medium, making this protocol eco-friendly.
- Jadhav, Sanjay N.,Rode, Chandrashekhar V.
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supporting information
p. 5958 - 5970
(2017/12/26)
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- A convenient, efficient and reusable N-heterocyclic carbene-palladium(II) based catalyst supported on magnetite for Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions
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In the present work, a new magnetic nanoparticle supported N-heterocyclic carbene-palladium(ii) (NO2-NHC-Pd@Fe3O4) nanomagnetic catalyst was synthesized by a facile multistep synthesis under aerobic conditions using inexpensive chemicals. The NO2-NHC-Pd@Fe3O4 nanomagnetic catalyst was characterized by various analytical techniques such as attenuated total reflectance infrared spectroscopy (ATR-IR), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller surface area analysis (BET). The synthesized NO2-NHC-Pd@Fe3O4 nanomagnetic catalyst showed excellent catalytic activity in both Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions for various substrates under mild reaction conditions. Recovery of the NO2-NHC-Pd@Fe3O4 nanomagnetic catalyst from the reaction mixture was easily accomplished by applying an external magnet. The recovered NO2-NHC-Pd@Fe3O4 nanomagnetic catalyst exhibited very good catalytic activity up to seven recycles in Suzuki-Miyaura and five recycles in Mizoroki-Heck cross-coupling reactions without considerable loss of its catalytic activity.
- Kandathil, Vishal,Fahlman, Bradley D.,Sasidhar,Patil, Siddappa A.,Patil, Shivaputra A.
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p. 9531 - 9545
(2017/08/29)
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- ORGANIC REACTIONS CARRIED OUT IN AQUEOUS SOLUTION IN THE PRESENCE OF A HYDROXYALKYL(ALKYL)CELLULOSE OR AN ALKYLCELLULOSE
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The present invention relates to a method of carrying out an organic reaction in aqueous solution in the presence of a hydroxyalkyl(alkyl)cellulose or an alkylcellulose.
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Page/Page column 234; 235
(2017/08/21)
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- Bench-Stable and Recoverable Palladium(I) Dimer as an Efficient Catalyst for Heck Cross-Coupling
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The application of air- and moisture-stable dinuclear palladium(I) complex [Pd(μ-I)(Pt-Bu3)]2 as an efficient catalyst for the Heck cross-coupling reaction of aryl iodides and bromides with acrylates and styrenes is described. The de
- Sperger, Theresa,Stirner, Christopher K.,Schoenebeck, Franziska
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supporting information
p. 115 - 120
(2016/12/24)
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- Cyclodextrin-Grafted Silica-Supported Pd Nanoparticles: An Efficient and Versatile Catalyst for Ligand-Free C-C Coupling and Hydrogenation
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Silica is an extremely versatile support, which is capable of hosting metal nanoparticles (NPs) and enhancing their stability and reactivity. In this study, a novel cyclodextrin/silica support for Pd NPs, which we have denoted Pd/Si-CD, has been prepared. The highly efficient and homogeneous impregnation of small palladium nanoparticles on this support has been carried out under conventional conditions, and ultrasound irradiation has been shown to have a beneficial effect on catalyst preparation. The catalyst exhibited excellent activity in ligand-free C-C Suzuki and Heck couplings with a large number of aryl iodide and bromides, in which microwave irradiation use cuts down reaction time. Pd/Si-CD have shown high activity and selectivity in the hydrogenation reaction, and the semihydrogenation of phenyl acetylene was also studied with excellent results.
- Martina, Katia,Baricco, Francesca,Caporaso, Marina,Berlier, Gloria,Cravotto, Giancarlo
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p. 1176 - 1184
(2016/04/05)
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- Palladium-catalyzed Heck coupling of arylhydrazines via C-NHNH2 bond activation
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A novel palladium-catalyzed Heck coupling reaction of arylhydrazines with olefins is described, which affords various styrenes with high efficiency. This transformation proceeds through a C-NHNH2 bond activation under mild conditions.
- Liu, Jin-Biao,Chen, Fu-Jiao,Liu, Na,Hu, Jiang
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p. 45843 - 45846
(2015/06/08)
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- Polyaniline-anchored palladium catalyst-mediated Mizoroki-Heck and Suzuki-Miyauraa reactions and one-pot Wittig-Heck and Wittig-Suzuki reactions
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A polyaniline-anchored palladium catalyst was prepared and screened for coupling reactions of aryl halides. The robust and recyclable catalyst was effective in Mizoroki-Heck and Suzuki-Miyaura reactions of aryl bromides and aryl iodides. The catalyst system was further employed for one-pot Wittig-Heck and Wittig-Suzuki combinations to build conjugated compounds in good conversions.
- Patel, Heta A.,Patel, Arun L.,Bedekar, Ashutosh V.
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- An efficient trifunctional benzhydrazone ligated Pd(II) complex for Heck reaction of aryl bromides
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Synthesis of air and thermally stable trifunctional O, N, and O-terdentate benzhydrazone Pd(II) complex is reported and characterized by elemental analysis, spectral methods, and single crystal X-ray crystallographic technique. The new and reusable homogeneous catalyst has been effectively applied to the Mizoroki-Heck reaction of activated and deactivated aryl bromides with various olefins under mild reaction conditions in good to excellent yields up to 99%.
- Muthumari, Subramanian,Mohan, Nanjan,Ramesh, Rengan
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supporting information
p. 4170 - 4174
(2015/06/22)
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- Improving reactivity and selectivity of aqueous-based Heck reactions by the local hydrophobicity of phosphine ligands
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Modification of a triarylphosphine with a cholate moiety affords a new ligand, 1, which is effective in palladium-catalyzed Heck cross-couplings between acrylates and aryl iodides under mild, aqueous reaction conditions. High yields, up to 99%, were achieved in water at 40 °C. In competition studies, a more hydrophobic substrate (n-Bu acrylate) was preferred over the least hydrophobic substrate (methyl acrylate), supportive of a localized hydrophobic microenvironment near the catalytic center. The enhanced reactivity and selectivity for hydrophobic substrates disappeared when the local hydrophobicity was eliminated using a standard water-soluble phosphine or in organic solvents.
- Roberts, Gina M.,Zhang, Shiyong,Zhao, Yan,Woo, L. Keith
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p. 8263 - 8270
(2015/10/05)
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- Pd(OAc)2-Catalyzed, AgOAc-Promoted Z Selective Directed β-Arylation of Acrylamide Systems and Stereoselective Construction of Z-Cinnamamide Scaffolds
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A Pd(OAc)2-catalyzed, AgOAc-promoted and bidentate ligand-directed Z selective C-H activation, followed by the β-arylation of the C(sp2)-H bond of N-(quinolin-8-yl)acrylamide systems with aryl- and heteroaryl iodides, and a contemporary method for the construction of various Z-cinnamamides and β,β-diarylated acrylamides are reported. A plausible reaction mechanism comprising the bidentate ligand-aided, chelation-based C-H functionalization was proposed for the observed Z selective β-arylation of N-(quinolin-8-yl)acrylamide systems.
- Parella, Ramarao,Babu, Srinivasarao Arulananda
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p. 12379 - 12396
(2016/01/09)
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- Adhesive catalyst immobilization of palladium nanoparticles on cotton and filter paper: Applications to reusable catalysts for sequential catalytic reactions
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Palladium nanoparticles dispersed in ammonium salts of hyperbranched polystyrenes are adhesively immobilized on the surface of cotton or filter papers by simply heating with dicarboxylic acids or halide anions. The resulting Pd@cotton and Pd@filter paper
- Nishikata, Takashi,Tsutsumi, Hironori,Gao, Lei,Kojima, Keisuke,Chikama, Katsumi,Nagashima, Hideo
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supporting information
p. 951 - 960
(2014/04/03)
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- Coordinated and uncoordinated anion dictated coordination mode of PN(Me)P ligand in Pd(II) complexes and their catalytic applications
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The PN(Me)P ligands based complexes [(η2-PN(Me)P Ph)PdCl2] (1), [(η3-PN(Me)P Ph)PdCl](OTf) (2) and [(η3-PNPiPr)PdCl] (3) (complexes 2 and 3 are pincer type) have been synthesized and characterized using standard analytical methods such as 1H NMR, 31P NMR, elemental analysis, UV-Visible spectroscopy, cyclic voltammetry and single-crystal X-ray crystallography. Formation of complexes 1 and 2 were observed under two different reaction conditions and learned about how the anions can dictate the coordination mode of PNP ligand to have different hapticity to offer different complexes. More importantly, isolation of complexes 1 and 2 filled the gap in PNP-Pd chemistry. DFT calculations have been carried out to understand the C-N bond cleavage of PN(Me)P ligand when -Ph and - iPr substituent introduced on the phosphorous. The complete reversible pattern of cyclic voltammogram of complex 3 suggests that this complex can be a better catalyst where two different oxidation states involve in the catalytic cycle. We have also performed Heck and Suzuki coupling reactions using complexes 1 and 3 and observed reasonably good yield even at relatively low temperature.
- Tamizmani, Masilamani,Kankanala, Ramakrishna,Sivasankar, Chinnappan
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supporting information
p. 6 - 13
(2014/05/20)
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- Template-directed synthesis of palladium(II) sulfonate-NHC complexes and catalytic studies in aqueous Mizoroki-Heck reactions
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Oxidation of easily accessible thiolato-functionalized dinuclear Pd(II) NHC complexes 1-3 by Oxone gave rise to sulfonate-NHC complexes 4-6. This represents the first template-directed approach to NHC complexes bearing sulfonate functions, where the sulfu
- Yuan, Dan,Teng, Qiaoqiao,Huynh, Han Vinh
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p. 1794 - 1800
(2014/05/06)
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- Time-dependent stereoselective Heck reaction using mesoporous Pd/TiO 2 nanoparticles catalyst under sunlight
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Pd(0)-doped mesoporous TiO2 nanoparticles (Pd/TiO2) have been synthesized using an EISA method. The catalytic activity of Pd/TiO2 nanoparticles (NPs) is significantly enhanced under solar light irradiation for the Heck reaction. The Heck coupling product gives a considerable amount of Z-isomer, due to photochemical isomerization of the initially formed E-isomer, providing a facility for the time-dependent selectivity of E/Z-isomers under sunlight at ambient conditions. The Royal Society of Chemistry.
- Soni, Saurabh S.,Kotadia, Deepali A.
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p. 510 - 515
(2014/02/14)
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- Pd doped SiO2 nanoparticles: An efficient recyclable catalyst for Suzuki, Heck and Sonogashira reactions
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Palladium doped silica (Pd/SiO2) mesoporous material was synthesized via the sol-gel route using the P123 triblock copolymer as a structure directing agent. Pd/SiO2 was efficiently used as a catalyst for Suzuki, Heck and Sonogashira reactions under microwave irradiation. The catalyst exhibited high activity for all the coupling reactions and can be recycled nine times without a significant loss in its catalytic activity. This journal is the Partner Organisations 2014.
- Kotadia, Deepali A.,Patel, Urmila H.,Gandhi, Sahaj,Soni, Saurabh S.
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p. 32826 - 32833
(2014/08/18)
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- Controlling olefin isomerization in the heck reaction with neopentyl phosphine ligands
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The use of neopentyl phosphine ligands was examined in the coupling of aryl bromides with alkenes. Di-tert-butylneopentylphosphine (DTBNpP) was found to promote Heck couplings with aryl bromides at ambient temperature. In the Heck coupling of cyclic alkenes, the degree of alkene isomerization was found to be controlled by the choice of ligand with DTBNpP promoting isomerization to a much greater extent than trineopentylphosphine (TNpP). Under optimal conditions, DTBNpP provides high selectivity for 2-aryl-2,3-dihydrofuran in the arylation of 2,3-dihydrofuran, whereas TNpP provided high selectivity for the isomeric 2-aryl-2,5-dihydrofuran. A similar complementary product selectivity is seen in the Heck coupling of cyclopentene. Heck coupling of 2-bromophenols or 2-bromoanilides with 2,3-dihydrofurans affords 2,5-epoxybenzoxepin and 2,5-epoxybenzazepins, respectively.
- Lauer, Matthew G.,Thompson, Mallory K.,Shaughnessy, Kevin H.
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p. 10837 - 10848
(2015/01/08)
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- "nok": A phytosterol-based amphiphile enabling transition-metal-catalyzed couplings in water at room temperature
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The third-generation designer amphiphile/surfactant, "Nok" (i.e., SPGS-550-M; β-sitosterol methoxypolyethyleneglycol succinate), soon to be commercially available from Aldrich, can be prepared in two steps using an abundant plant feedstock and β-sitosterol, together with succinic anhydride and PEG-550-M. Upon dissolution in water, it forms nanomicelles that serve as nanoreactors, which can be characterized by both cryo-TEM and dynamic light scattering analyses. Several transition-metal-catalyzed reactions have been run under micellar conditions to evaluate this surfactant relative to results obtained in nanoparticles composed of TPGS-750-M (i.e., a second-generation surfactant). It is shown that Nok usually affords yields that are, in general, as good or better than those typically obtained with TPGS-750-M, and yet is far less costly.
- Klumphu, Piyatida,Lipshutz, Bruce H.
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p. 888 - 900
(2014/03/21)
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- Flow-based, cerium oxide enhanced, low-level palladium sonogashira and heck coupling reactions by perovskite catalysts
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A flow chemistry procedure for Sonogashira and Heck cross-coupling reactions using a low-level palladium perovskite catalyst (LaFe 0.95Pd0.05O3) deposited on cerium oxide is reported. The catalyst was generated in situ at
- Battilocchio, Claudio,Bhawal, Benjamin N.,Chorghade, Rajeev,Deadman, Benjamin J.,Hawkins, Joel M.,Ley, Steven V.
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p. 371 - 380
(2014/05/06)
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- Heck and Sonogashira cross-coupling reactions using recyclable Pd-Fe 3O4 heterodimeric nanocrystal catalysts
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We have developed a convenient Pd-Fe3O4 heterodimeric nanocrystal catalyst system for Heck and Sonogashira reactions. This catalyst offers an environment-friendly, atom-efficient, and robust catalytic system for both reactions. Furthermore the nanocrystal catalyst could be easily separated by an external magnet and recycled six times without losing its catalytic activity.
- Chung, Jooyoung,Kim, Jinju,Jang, Youngjin,Byun, Sangmoon,Hyeon, Taeghwan,Kim, B. Moon
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p. 5192 - 5196
(2013/09/02)
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- Heck-Matsuda reaction of arenediazonium salts in water
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The palladium-catalyzed arylation of alkenes with aryldiazonium salts can be carried out through an environmentally friendly protocol using neat water low palladium loadings at room temperature under base-additive- and ligand-free conditions.
- Salabert, Jordi,Sebastián, Rosa María,Vallribera, Adelina,Cívicos, José Francisco,Nájera, Carmen
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p. 2655 - 2659
(2013/03/28)
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- A simple catalytic system based on PdCl2(CH3CN) 2 in water for cross-coupling reactions using diazonium salts
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Aryl-heteroaryl and heteroaryl-heteroaryl compounds are obtained through the Suzuki-Miyaura cross-coupling reactions between diazonium salts and potassium trifluoroborates using PdCl2(CH3CN)2 as the catalyst in water and in the absence of any additive, ligand or base. In addition, the same mild catalytic system is effective for the Matsuda-Heck reaction between several monoolefins with aryldiazonium salts.
- El Bakouri, Ouissam,Fernández, Martí,Brun, Sandra,Pla-Quintana, Anna,Roglans, Anna
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p. 9761 - 9765
(2013/10/22)
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- Crystalline hybrid solid materials of palladium and decamethylcucurbit[5] uril as recoverable precatalysts for heck cross-coupling reactions
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A series of M-Pd-Me10CB[5] (M=Li, Na, K, Rb, and Cs; Me 10CB[5]=decamethylcucurbit[5]uril) hybrid solid materials have been successfully synthesized for the first time through a simple diffusion method. These as-prepared hybrid solids have been applied as phosphine-free precatalysts for Heck cross-coupling reactions with excellent catalytic performance and good recyclability. In the processes of the catalytic reactions, the activated PdII species were released from the crystalline hybrid precatalysts and transformed into catalytically active Pd nanoparticles, which have been demonstrated as key to carry on the catalytic reactions for the recoverable precatalysts M-Pd-Me10CB[5] (M=K, Rb, and Cs). It has also been rationalized that the introduction of different alkali metals afforded crystalline hybrid precatalysts with different crystal structures, which are responsible for their diversified stability and reusability presented in Heck reactions. Hybrid cats: A series of crystalline hybrid solid materials of palladium and decamethylcucurbit[5]uril (M-Pd-Me10CB[5], in which M=Li, Na, K, Rb, and Cs) have been successfully synthesized for the first time by means of a simple diffusion method. These as-prepared hybrid solids have been applied as phosphine-free precatalysts for Heck cross-coupling reactions with excellent catalytic performance and good recyclability (see figure). Copyright
- Li, Hongfang,Lue, Jian,Lin, Jingxiang,Huang, Yuanbiao,Cao, Minna,Cao, Rong
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p. 15661 - 15668
(2013/11/19)
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- Monomeric Pd(II) complexes with trans-chelated pyrazole ligands as effective pre-catalysts for Heck cross-coupling reaction under mild aerobic conditions
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A new family of mononuclear palladium(II) complexes with bidentate trans-chelating pyrazole ligands [PdCl2(LR)] (R = H, 1; Et, 2; Ph, 3; CHPh2, 4), where new ligand LEt = 2-ethyl-1,3-bis-(3,5-dimethyl-pyrazol-1-
- Chou, Chang-Chuan,Yang, Chia-Chi,Syu, Hong-Bin,Kuo, Ting-Shen
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p. 387 - 392
(2013/10/01)
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- Poly(ethylene glycol) as reaction medium for mild Mizoroki-Heck reaction in a ball-mill
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Phosphine-free palladium-catalyzed Mizoroki-Heck reaction was performed using ball-milling in polyethylene glycol under mild conditions. Good to excellent yields of coupling products were obtained. This activation technique also allowed the concomitant fo
- Declerck, Valerie,Colacino, Evelina,Bantreil, Xavier,Martinez, Jean,Lamaty, Frederic
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p. 11778 - 11780
(2013/01/15)
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- Organocatalytic deprotonative functionalization of C(sp2)-H and C(sp3)-H bonds using in situ generated onium amide bases
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Onium amides, generated in situ from the combination of aminosilanes and onium fluorides (R4PF, R4NF), are employed for the first time as bases for catalytic deprotonative functionalization of C(sp 2)-H and activated C(sp
- Inamoto, Kiyofumi,Okawa, Hitomi,Taneda, Hiroshi,Sato, Maomi,Hirono, Yutaro,Yonemoto, Misato,Kikkawa, Shoko,Kondo, Yoshinori
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supporting information
p. 9771 - 9773,3
(2020/08/31)
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- Dipalladium complexes with triazolidin-diylidene bridges and their catalytic activities
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The 1,2,4-trimethyltriazolidin-3,5-diylidene (ditz) bridged dipalladium heterotetracarbene complex [PdBr2(iPr2-bimy)] 2(μ-ditz) (3) (iPr2-bimy = 1,3-diisopropylbenzimidazolin-2-ylidene) was prepared by Ag-carbene transfer involving the 1,2,4-trimethyltriazolium dication (C), Ag2O, and the precursor complex (iPr2-bimyH)[PdBr3( iPr2-bimy)] (2). Bromido substitution of 3 with AgO 2CCH3 and AgO2CCF3afforded the carboxylato complexes [Pd(O2CCH3)2( iPr2-bimy)]2(μ-ditz) (4) and [Pd(O 2CCF3)2(iPr2-bimy)] 2(μ-ditz) (5). Multinuclei NMR spectroscopies and X-ray diffraction analyses showed that the all-trans isomers of 3, 4, and 5 are the predominant products in all three cases. In addition, the decomposition product of complex 4, trans-[Pd(O2CCH3)2( iPr2-bimy)2] (trans-6) was structurally determined by X-ray crystallography. A comparative catalytic study revealed the superiority of complexes 3, 4, and 5 over the previously reported mononuclear bis(benzimidazolin-2-ylidine) complexes without ditz bridges in the Mizoroki-Heck coupling reaction. Overall, complex 4 bearing acetato coligands showed the best catalytic performance.
- Guo, Shuai,Huynh, Han Vinh
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experimental part
p. 4565 - 4573
(2012/07/27)
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- Synthesis and ring openings of cinnamate-derived N-unfunctionalised aziridines
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Tert-Butyl cinnamates are aziridinated with high trans-selectivity by an N-N ylide generated in situ from N-methylmorpholine and O-diphenylphosphinyl hydroxylamine. The resulting N-unfunctionalised aziridines are shown to be versatile synthetic building b
- Armstrong, Alan,Ferguson, Alexandra
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supporting information
p. 1747 - 1752,6
(2020/09/16)
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- Catalytic application of dinuclear palladium(II) bis(thiosemicarbazone) complex in the Mizoroki-Heck reaction
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A convenient synthesis of new square planar dinuclear palladium(II) terephthaldehyde bis(thiosemicarbazone) complex has been described. The compositions of the complex have been established by elemental analysis, spectral methods and single crystal X-ray crystallographic technique. The new complex acts as an active recyclable homogeneous catalyst for the Mizoroki-Heck reaction of electron deficient (activating) and electron rich (deactivating) aryl halides with various olefins under optimized conditions.
- Prabhu, Rupesh Narayana,Ramesh, Rengan
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supporting information
p. 5961 - 5965,5
(2020/08/20)
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- Magnetic nanoparticles-supported palladium: A highly efficient and reusable catalyst for the Suzuki, Sonogashira, and heck reactions
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A highly efficient, air- and moisture-stable and easily recoverable magnetic nanoparticle-supported palladium catalyst has been developed for the Suzuki, Sonogashira and Heck reactions. A wide range of substrates was coupled successfully under aerobic conditions. In particular, the performance of the magnetic separation of the catalyst was very efficient, and it is possible to recover and reuse it at least eight times without significant loss of its catalytic activity. Copyright
- Li, Pinhua,Wang, Lei,Zhang, Lei,Wang, Guan-Wu
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supporting information; experimental part
p. 1307 - 1318
(2012/06/15)
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