- Highly efficient nickel-catalyzed Heck reaction using Ni(acac)2/ N-heterocyclic carbene catalyst
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Ni(acac)2/N-heterocyclic carbene-derived catalysts were shown to be highly efficient in the nickel-catalyzed Heck reaction. Various aryl halides were reacted with acrylate to give the coupled products in good to high yield. Georg Thieme Verlag
- Inamoto, Kiyofumi,Kuroda, Jun-Ichi,Danjo, Tomohiro,Sakamoto, Takao
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- Direct intermolecular hydroacylation of N,N-dialkylacrylamides with aldehydes catalyzed by a cationic rhodium(I)/dppb complex
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Figure presented A cationic rhodium(l)/dppb complex catalyzed direct intermolecular hydroacylation of N,N-dialkylacrylamides with both aliphatic and aromatic aldehydes has been achieved through the stabilization of acylrhodium intermediates by alkene chel
- Tanaka, Ken,Shibata, Yu,Suda, Takeshi,Hagiwara, Yuji,Hirano, Masao
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- Palladium-containing ionic liquid-based ordered mesoporous organosilica: An efficient and reusable catalyst for the heck reaction
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The catalytic application of a novel palladium-containing periodic mesoporous organosilica with ionic liquid framework (Pd@PMO-IL-I) in the Heck cross-coupling reaction was described. This nanocatalyst was first synthesised and characterised by using diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetric analysis, transmission electron microscopy and nitrogen sorption analysis. The efficiency of the Pd@PMO-IL-I catalyst was investigated in the Heck cross-coupling of various aryl halides with alkyl acrylates in the presence of N-methylpyrolidone at 140°C. The catalyst demonstrated excellent catalytic activity with various aryl iodides, aryl bromides, and activated aryl chlorides, which gave the corresponding coupling products in good to excellent yields and with excellent E-selectivities. Moreover, the recoverability, reusability and the actual nature of the Pd@PMO-IL-I catalyst were investigated to show the effect of ionic liquid moieties on the stabilisation of palladium species during the reaction. Our study showed that the catalyst could be recovered and reused at least nine times without any appreciable decrease in activity and selectivity, which confirmed its high efficiency and high stability under the reaction conditions and during recycling stages.
- Elhamifar, Dawood,Karimi, Babak,Rastegar, Javad,Banakar, Mohammad Hossain
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- Kinetic studies of heck coupling reactions using palladacycle catalysts: Experimental and kinetic modeling of the role of dimer species
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Experimental kinetic studies of the coupling of p-bromobenzaldehyde (1) with butyl acrylate (2) using the dimeric palladacycles complex (4) with chelating nitrogen ligands were carried out together with kinetic modeling using a reaction rate expression ba
- Rosner,Le Bars,Pfaltz,Blackmond
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- Synthesis of vinylated 5,10,15,20-tetraphenylporphyrins via heck-type coupling reaction and their photophysical properties
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The direct coupling reaction between substituted olefins and 5,10,15,20-tetrakis(4-bromophenyl)porphyrin, via a Heck-type reaction, constitutes a versatile method for the vinylation of 5,10,15,20-tetrakis(4-bromophenyl)porphyrin to yield new vinylated tetraphenylporphyrins quantitatively. Another strategy for the vinylporphyrin synthesis has been developed. A phosphapalladacycle has been used as catalyst for the coupling reaction between 4-bromoaryl aldehydes and olefins to yield vinyl aldehydes quantitatively. These aldehydes have been condensed with pyrrole, by the one-step nitrobenzene method, to give the corresponding vinylated tetraphenylporphyrins. Photophysical studies of these new porphyrins are also reported.
- Pereira, Mariette M.,Muller, Guillermo,Ordinas, Juan Ignacio,Azenhaa, M. Emilia,Arnaut, Luis G.
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- Comprehensive kinetic screening of palladium catalysts for heck reactions
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Comprehensive kinetic screening of Pd catalysts for Heck reactions via a consecutive pulse reaction methodology allows a more informed choice of catalyst for a particular transformation, taking into account not only initial reactivity but also long-term c
- Blackmond, Donna G.,Schultz, Thomas,Mathew, Jinu S.,Loew, Caroline,Rosner, Thorsten,Pfaltz, Andreas
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- Synthesis of pyrazine-bridged diimidazolium salts and their application in palladium catalyzed Heck-type coupling reactions
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Reaction of imidazole derivatives with 2,3-di(bromomethyl)pyrazine results in the formation of the new pyrazine-bridged diimidazolium salts 1-8. These salts proved to be valuable precursors for dinuclear complexes with mixed NHC/pyrazine ligands. Two of t
- Jahnke, Mareike C.,Hussain, Mukhtiar,Hupka, Florian,Pape, Tania,Ali, Saqib,Hahn, F. Ekkehardt,Cavell, Kingsley J.
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- Palladium Complexes with Phenoxy- And Amidate-Functionalized N-Heterocyclic Carbene Ligands Based on 3-Phenylimidazo[1,5- a]pyridine: Synthesis and Catalytic Application in Mizoroki-Heck Coupling Reactions with Ortho-Substituted Aryl Chlorides
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Mononuclear and tetranuclear palladium complexes with functionalized "abnormal"N-heterocyclic carbene (aNHC) ligands based on 3-phenylimidazo[1,5-a]pyridine were synthesized. All of the new complexes were structurally characterized by single-crystal X-ray diffraction studies. The new complexes were applied in the Mizoroki-Heck coupling reaction of aryl chlorides with alkenes in neat n-tetrabutylammonium bromide (TBAB). The mononuclear palladium complex with a tridentate phenoxy- and amidate-functionalized aNHC ligand displayed activity superior to that of the palladium complex with a bidentate amidate-functionalized aNHC ligand. The new tetranuclear complex with the tridentate ligand displayed the best activities, capable of the activation of deactivated aryl chlorides as substrates with a low Pd atom loading. Even challenging sterically demanding ortho-substituted aryl chlorides were successfully utilized as substrates. The studies revealed that the robustness of the catalyst precursor is crucial in delivering high catalytic activities. Also, the promising use of tetranuclear palladium complexes with functionalized aNHC ligands as the catalyst precursors in the Mizoroki-Heck coupling reaction in neat TBAB was demonstrated.
- Hung, Cheng-Hau,Zheng, Wei-Yuan,Lee, Hon Man
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p. 702 - 713
(2021/04/02)
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- PdII Immobilized on Ferromagnetic Multi-Walled Carbon Nanotubes Functionalized by Aminated 2-Chloroethylphosphonic Acid with S -Methylisothiourea (FMMWCNTs@CPA@SMTU@PdII NPs) Applied as a Highly Efficient and Recyclable Nanostructured Catalyst for Suzuki-Miyaura and Mizoroki-Heck Cross-Coupling Reactions in Solvent-Free Conditions
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The new ferromagnetic nanostructured FMMWCNTs@CPA@SMTU@PdII NPs (IV) as an eco-friendly heterogeneous nanocatalyst with a particle size of ~20-30 nm reported earlier by our group has been found to be very effective for Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions at ambient temperature. The procedure has been applied for a wide range of aryl halides, arylboronic acids, and alkenes. The magnetic separation by an external magnetic field, mild reaction conditions, and catalyst reusability up to four times without significant decrease in catalytic activity (reduced catalytic activity from 11 to 18 % in the fifth, sixth, and seventh cycles) made the present method sustainable and economically viable for C-C cross-coupling reactions.
- Ghasemzadeh, Maryam Sadat,Akhlaghinia, Batool
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p. 674 - 692
(2019/07/12)
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- Efficient Mizoroki–Heck coupling reactions using phosphine-modified Pd(II)–picolinate complex
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Efficient Mizoroki–Heck couplings were obtained using a very easily synthesizable palladium(II) complex of hemilabile N–O ligand (picolinate), with high turnover frequencies up to >10,000 h?1, in just 15 min, with high selectivity of >99% to the desired products. Wide applicability of the simple-looking palladium complex catalyst was established with differently functionalized substrates. Catalyst screening studies revealed intricate details of dependence of catalyst performance on different reaction parameters and conditions and arriving at the optimized facile methodology.
- Sharma, Sonam,Sarkar, Bibhas R.
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supporting information
p. 906 - 914
(2018/03/21)
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- Synthesis and Characterization of C, C -Type Palladacycles and Their Catalytic Application in Mizoroki-Heck Coupling Reaction
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Two series of ligand precursors, based on imidazo[1,2-a]pyridine and C2-phenyl substituted imidazole moieties, were developed and synthesized in high yields, featuring an N-CH2(C=O)Ar substituent on the imidazole ring. Upon reacting with palladium acetate, both series of ligands underwent double C-H bond activations at the methylene and o-aryl carbon sites on the N-CH2(C=O)Ar substituent, yielding C,C-type palladacycles bearing five-membered chelate rings. A dimeric palladium complex with bridging bromides was obtained from the ligand precursor with the bromide anion, whereas an ionic palladium complex with two "throw away" pyridine ligands was formed with the precursor of the tetrafluoroborate anion. All complexes are air-stable and were characterized by 1H and 13C NMR spectroscopy and elemental analysis. The structures of three of the new complexes were further established by single-crystal X-ray diffraction studies. These complexes have been screened for catalyzing Mizoroki-Heck coupling reaction using ionic salt as solvent. The complex based on imidazo[1,2-a]pyridine, which has an electron-donating 4-methoxyphenyl ring on the ligand scaffold, was the most efficient catalyst, capable of using activated aryl chloride and sterically hindered aryl bromide as substrates. It was also successfully applied in the green process of one-pot Mizoroki-Heck coupling/trans-esterification reaction in molten ionic salt.
- Lo, Chi Hou,Lee, Hon Man
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p. 1150 - 1159
(2018/04/17)
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- A Palladium NNC-Pincer Complex as an Efficient Catalyst Precursor for the Mizoroki?Heck Reaction
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The Mizoroki?Heck reaction of aryl halides (iodides, bromides, or chlorides) with activated alkenes in the presence of a palladium NNC-pincer complex at ppb to ppm loadings gave the corresponding internal alkenes in excellent yields. The total turnover number and turnover frequency reached up to 8.70×108 and 1.21×107 h?1 (3.36×103 s?1), respectively. The catalyst was applied in a ten-gram-scale synthesis of the UV-B sunscreen agent octinoxate (2-ethylhexyl 4-methoxycinnamate). Reaction-rate analyses, transmission electron microscopic examination of the reaction mixture, and poisoning tests suggested that a monomeric palladium species is the catalytically active species in the catalytic cycle. (Figure presented.).
- Hamasaka, Go,Ichii, Shun,Uozumi, Yasuhiro
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supporting information
p. 1833 - 1840
(2018/04/05)
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- Macrocyclic Pd(II) dithiolate complexes as catalysts in Heck reactions
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The supramolecular palladium dithiolate complexes, [Pd2(dppe)2{S(C6H4)nS}]2(OTf)4and [Pd2(dppe)2(SCH2C6H4CH2S)]
- Mane, Pravin A.,Dey, Sandip,Vivekananda
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supporting information
p. 25 - 29
(2016/12/23)
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- In situ generation of highly active bis(N-heterocyclic)carbene palladium as an efficient catalyst in direct S-arylation of methylphenyl sulfoxide and the Heck reaction: Ligand steric effects in product selectivity
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The use of 1,3-bis(N-heterocyclic)carbene ligands with different alkyl wingtip groups (alkyl = methyl, isopropyl and tert-butyl) is an effective method for the palladium-catalysed direct S-arylation of methylphenyl sulfoxide and C–C coupling of various of aryl halides with alkenes. The reactions proceed in moderate to good yields. Interestingly, it is shown experimentally that, by using bulkier bidentate N-heterocyclic carbene ligands, more selective catalytic systems towards cis products in Heck coupling reactions can be achieved.
- Bagherzadeh, Mojtaba,Mousavi, Narges-Alsadat,Jamali, Sirous
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- Fe3O4@Boehmite-NH2-CoII NPs: An inexpensive and highly efficient heterogeneous magnetic nanocatalyst for the Suzuki-Miyaura and Heck-Mizoroki cross-coupling reactions
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Herein we report the synthesis of a magnetically separable core-shell-like Fe3O4@Boehmite-NH2-CoII NPs as an environmentally friendly heterogeneous catalyst. The as-prepared nanocatalyst was well characterized by various techniques such as FT-IR, XRD, BET, TEM, FE-SEM, EDX, TGA, H2-TPR, VSM, ICP-OES and elemental analysis and evaluated for the Suzuki-Miyaura and Heck-Mizoroki cross-coupling reactions in a green solvent (H2O). The results of characterization studies revealed the superparamagnetic behavior of the Fe3O4 NP core encapsulated by a Boehmite NP shell. Also, it was clearly found that the size of the particles was about 13-54 nm. In comparison with previously reported catalysts, Fe3O4@Boehmite-NH2-CoII NPs exhibited perfect catalytic efficiency for the Suzuki-Miyaura and Heck-Mizoroki cross-coupling reactions under mild conditions without using toxic solvents. The concerted effects between individual components of the catalyst and also its unique egg-like nanostructure led to the high catalytic performance of Fe3O4@Boehmite-NH2-CoII NPs. Also, the introduction of Co significantly lowers the cost of the catalyst. More importantly, the longevity of the nanocatalyst was studied and it was found that the magnetic nanocatalyst was stable under the reaction conditions and could be easily reused for at least seven consecutive cycles without a discernible decrease in its catalytic activity or metal leaching.
- Mohammadinezhad, Arezou,Akhlaghinia, Batool
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p. 5625 - 5641
(2017/12/06)
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- Well-defined palladium(0) complexes bearing N-heterocyclic carbene and phosphine moieties: Efficient catalytic applications in the Mizoroki-Heck reaction and direct C-H functionalization
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Two series of well-defined palladium(0) complexes with phosphine-functionalized N-heterocyclic carbene ligands were prepared. These complexes featured six- and seven-membered chelate rings in the two series. Among the seven-membered chelate complexes, those featuring the PCy2 moiety exhibited observable fluxional behavior on the NMR time scale, corresponding to the interchange between two sets of conformations. Most of these novel complexes were successfully structurally characterized by single-crystal X-ray diffraction studies. These two series of palladium(0) complexes were tested for their potential catalytic applications in two mechanistically distinct reactions, namely, Mizoroki-Heck coupling and direct C-H functionalization reactions. One of the six-membered chelate complexes was found to be an efficient pre-catalyst for mediating the coupling reactions between aryl chlorides and alkenes. The palladium(0) complex could also be effectively applied in the direct C-H functionalization reactions of aryl bromides with 1,2-dimethylimidazole.
- Lee, Jhen-Yi,Shen, Jiun-Shian,Tzeng, Ru-Jiun,Lu, I-Chen,Lii, Jenn-Huei,Hu, Ching-Han,Lee, Hon Man
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p. 10375 - 10388
(2016/07/06)
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- 1,1′-methylene-3,3′-bis[(N -(tert -butyl)imidazol-2-ylidene] and Its effect in palladium-catalyzed C-C coupling
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A catalytic system utilizing a chelate carbene ligand containing bulk tert-butyl groups is described for palladium-catalyzed Heck and Suzuki coupling reactions. The Heck reaction focused on the coupling of different aryl bromides with mono- and 1,1-disubstituted olefins while the Suzuki reaction involved the coupling of aryl bromides and phenylboronic acid to afford the corresponding biphenyls. The catalyst system performs well with low Pd(OAc)2 levels (0.025 mol% Pd). In all cases with monosubstituted olefins, the trans-configured products were obtained, while the results of Heck reaction of 1,1-disubstituted olefins exhibited a high selectivity favoring the terminal product.
- Nadri, Shirin,Rafiee, Ezzat,Jamali, Sirous,Joshaghani, Mohammad
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supporting information
p. 619 - 624
(2015/03/14)
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- Assembly and post-modification of a metal-organic nanotube for highly efficient catalysis
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A metal-organic nanotube (MONT) was synthesized by linking up the bent organic ligands and the tetra-coordinated zinc cations under mild conditions. Structural analysis revealed that the MONT has a very large exterior wall diameter of 4.91 nm and an interior channel diameter of 3.32 nm. Interlocking of the nanotubes gives rise to a 3D chiral framework containing 1D helical cylindered channels with diameter of 2.0 nm. The MONT has very interesting property by synergizing the functionality of nanotubes, metal-organic frameworks (MOFs), and N-heterocyclic carbenes (NHCs). The dye adsorption experiments demonstrate that the channels of the MONTs are accessible to large reagents typically used for catalysis. The postmodification of the MONT can be easily operated by unmarking the imidazolium moieties in the channel walls, which was conducted as a highly active heterogeneous catalyst for Suzuki-Miyaura and Heck coupling reactions, hydrogenation of olefins and nitrobenzene, while the constituent elements are less efficient for these reactions under the same conditions.
- Kong, Guo-Qiang,Ou, Sha,Zou, Chao,Wu, Chuan-De
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p. 19851 - 19857
(2013/02/22)
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- Palladium nanoparticles generated from allylpalladium chloride in situ: A simple and highly efficient catalytic system for Mizoroki-Heck reactions
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The Mizoroki-Heck reactions of aryl halides catalyzed by palladium nanoparticles generated in situ from a simple allyl palladium precursor were investigated in argon. The high turnover numbers of 9,300,000 have been obtained with 4-bromobenzonitrile as substrate and 3500 with 4-nitrochlorobenzene. When the reaction was performed in air, a low yield was given, but it could be improved obviously by addition of PEG-400. The main reason was that inactive Pd(II) species could be rapidly reduced to the active Pd(0) by PEG. In other word, the existence of air and PEG led to a synergistic effect which the oxidation by air prevents the aggregation of Pd NPs and the reduction by PEG maintains the high activity of Pd(0) species.
- Wang, Wei,Yang, Qin,Zhou, Rong,Fu, Hai-Yan,Li, Rui-Xiang,Chen, Hua,Li, Xian-Jun
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experimental part
p. 1 - 5
(2012/01/13)
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- Bis-diimidazolylidine complexes of nickel: Investigations into nickel catalyzed coupling reactions
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Air and moisture stable homoleptic bis(diimidazolylidine)nickel(ii) complexes, ([(diNHC)2Ni]2+) 3a,b and their corresponding silver(i) 4a,b and palladium(ii) 5a,b complexes were synthesized and characterized by NMR and single crystal X-ray analysis. The catalytic potential of complex 3a was assessed in Mizoroki-Heck and Suzuki-Miyaura coupling reactions. In the Suzuki-Miyaura coupling reaction, nickel precatalyst 3a was active for the coupling of aryl chlorides as well as aryl fluorides. The analogously synthesized Pd(ii) complexes resulted in formation of (diNHC)PdCl2 species which were not active for the coupling of aryl fluorides. For the Mizoroki-Heck reaction, it was found that aryl iodides could be activated in the absence of nickel or palladium precatalysts when using Na2CO3 or NEt3 as base while aryl iodides and aryl bromides could be activated in the Suzuki-Miyaura reaction sans precatalyst when K3PO4 was used as base. The Royal Society of Chemistry.
- Paulose, Tressia A. P.,Wu, Shih-Chang,Olson, Jeremy A.,Chau, Tony,Theaker, Nikki,Hassler, Matt,Quail, J. Wilson,Foley, Stephen R.
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experimental part
p. 251 - 260
(2012/01/31)
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- Pyridazine-based N-heterocyclic carbene complexes and ruthenium-catalyzed oxidation reaction of alkenes
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[Ru2Cl(L)(CH3CN)4](PF6) 3 (1, L = 3,6-bis(N-(pyridylmethyl)imidazolylidenyl)pyridazine), [Cu3La3](PF6)3 (2, L a = 3-(N-(pyridylmethyl)imidazolylidenyl)-6-(N-(pyridylmethyl) imidazolylonyl)pyridazine), [Pd2(allyl)2L](PF 6)2 (3), [Pd2(allyl)2L b2](PF6)2 (4, Lb = N-pyridylmethylimidazole), and [NiLc2](PF 6)2 (5, Lc = 3-(N-(pyridylmethyl) imidazolylidenyl)-6-methoxylpyridazine) have been synthesized and fully characterized by NMR spectroscopy, elemental analysis, and X-ray diffraction analysis. In complex 1, ligand L binds to two Ru(II) centers, forming a well-behaved Ru2(L)Cl plane with a five-membered metallocyclic ring. Complex 2 is trinuclear, containing a triangular Cu3 unit bonded together by three 3-(N-(pyridylmethyl)imidazolylidenyl)-6-(N-(pyridylmethyl) imidazolylonyl)pyridazine, where one imidazolylidene was oxidized into imidazolone. Deprotonation reaction with Ag2O in CH3CN and CH3OH resulted in C-N cleavage of the imidazolium salt, and subsequent reaction with [Pd(allyl)Cl]2 and Ni(PPh3) 2Cl2 gave 4 and 5, respectively. Dinuclear Ru(II)-NHC complex 1 exhibits excellent catalytic activity for the oxidation of alkenes into diketones.
- Liu, Xiaolong,Chen, Wanzhi
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p. 6614 - 6622
(2012/11/06)
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- An efficient phosphine-free heck reaction in water using Pd(l -Proline)2 as the catalyst under microwave irradiation
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The present report describes an efficient and simple protocol for phosphine-free Heck reactions in water using a Pd(l-proline)2 complex as the catalyst under controlled microwave irradiation conditions. This methodology is versatile and provides excellent yields of products in short reaction times and minimizes costs, operational hazards and environmental pollution. Georg Thieme Verlag Stuttgart.
- Allam, Bharat Kumar,Singh, Krishna Nand
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experimental part
p. 1125 - 1131
(2011/05/14)
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- Palladium nanoparticles on graphite oxide as catalyst for Suzuki-Miyaura, Mizoroki-Heck, and Sonogashira reactions
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Pd2+-Exchanged graphite oxide (GO) serves as a precatalyst for the formation of Pd-nanoparticles which are then deposited on the highly functionalized carbonaceous support. This versatile, air-stable, and ligand-free system was applied successfully to Suzuki-Miyaura couplings of some aryl chlorides and to the Mizoroki-Heck as well as the Sonogashira reaction showing relatively high activities and good selectivities. Like with other ligand-free supported systems, the reaction proceeded dominantly by a homogeneous mechanism, but attack of an aryl iodide to Pd-nanoparticles can be excluded as substantial contribution to the entire catalytic process. Beside its straightforward preparation and its stability in air, the system combines the advantages of both homogeneous and heterogeneous catalysis.
- Rumi, Luigi,Scheuermann, Gil M.,Muelhaupt, Rolf,Bannwarth, Willi
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experimental part
p. 966 - 976
(2011/08/05)
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- Ligand-free copper-catalyzed arylation of olefins by the mizoroki-heck reaction
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A novel ligand-free copper-catalyzed Mizoroki-Heck cross-coupling reaction of various aryl iodides with olefins has been developed. Both the solvent and the base were found to have a fundamental influence on the efficiency of the transformation in the presence of 10 mol% Cu, with DMF and tetramethylammonium bromide (TMAB) being the optimal solvent and base, respectively. As a result, a set of the corresponding E-internal olefins were obtained selectively in moderate to good yields.
- Peng, Yong,Chen, Jiuxi,Ding, Jinchang,Liu, Miaochang,Gao, Wenxia,Wu, Huayue
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experimental part
p. 213 - 216
(2011/03/19)
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- Palladium-catalyzed heck reaction of aryl chlorides under mild conditions promoted by organic ionic bases
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An efficient Pd-catalyzed Heck reaction of aryl chlorides with olefins under mild conditions is described. High yields of products were achieved with n-Bu4N+OAc- as base. Significantly, the temperature of the Heck reaction of diverse nonactivated aryl chlorides can be lowered to 80 °C. The new reaction system can also tolerate a wider range of olefins.
- Xu, Hua-Jian,Zhao, Yong-Qiang,Zhou, Xin-Feng
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experimental part
p. 8036 - 8041
(2011/12/02)
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- A heteroleptic palladium(II) complex containing a bidentate carbene/amido ligand and 3-(trifluoromethyl)-5-(2-pyridyl)pyrazolate: Fast catalyst activation in the heck coupling reaction
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A multicomponent reaction between PdCl2, fppzH, and [LH 1H2]Cl in the presence of K2CO3 (L = bidentate amido/carbene; fppzH = 3-(trifluoromethyl)-5-(2-pyridyl)pyrazole) allows the preparation of PdL(fppz) in good yield. The analogous platinum complex, however, needs to be prepared by a two-step procedure. The new palladium(II) and platinum(II) complexes were characterized by 1D and 2D NMR spectroscopy, X-ray crystallography, electrospray ionization mass spectrometry, and elemental analyses. X-ray photoelectron spectroscopy indicates the high electron richness of the palladium atoms in PdL(fppz). These palladium complexes are efficient in catalyzing Heck coupling reactions with challenging aryl halide substrates. The catalyst activation in PdL(fppz) is significantly faster than that in cis-PdL2. A mere 0.5 mol % of palladium loading is enough to afford a 82% yield of coupled product from 4-chloroanisole and styrene in 24 h.
- Sie, Ming-Han,Hsieh, Yuan-Hsin,Tsai, Yi-Hua,Wu, Jia-Rong,Chen, Shih-Jung,Kumar, P. Vijaya,Lii, Jenn-Huei,Lee, Hon Man
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experimental part
p. 6473 - 6481
(2011/02/17)
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- Bio-supported palladium nanoparticles as a catalyst for Suzuki-Miyaura and Mizoroki-Heck reactions
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The biological synthesis of metal nanoparticles from ions has recently emerged as a novel technique for an environmentally benign recovery of heavy metals. Bacteria are known to recover palladium(0) in the form of nanoparticles that are catalytically active. However, the extent of the reactions that can be catalysed by bio-recovered palladium has not been investigated. This study demonstrates that the Suzuki-Miyaura and Mizoroki-Heck reactions can be catalysed by bio-generated palladium nanoparticles formed on the surface of Gram-negative bacteria. The results suggest that the range of applications of this catalyst can be extended to the realm of carbon-carbon bond formation in synthetic organic chemistry.
- Sobjerg, Lina Sveidal,Gauthier, Delphine,Lindhardt, Anders Thyboe,Bunge, Michael,Finster, Kai,Meyer, Rikke Louise,Skrydstrup, Troels
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scheme or table
p. 2041 - 2046
(2010/07/04)
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- Synthesis, structural characterization, and catalytic behaviour in Heck coupling of palladium(ii) complexes containing pyrimidine-functionalized N-heterocyclic carbenes
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[Pd(L1)2(CH3CN)](PF6)2 (L1 = 1-n-butyl-3-(2-pyrimidyl)imidazolylidene, 3) and [Pd(L2)2](PF 6)2 (L2 = 1-(2-picolyl)-3-(2-pyrimidyl)imidazolylidene 4), prepared via carbene transfe
- Ye, Jiansheng,Chen, Wanzhi,Wang, Daqi
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scheme or table
p. 4015 - 4022
(2009/02/03)
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- Syntheses, structures, and coordination chemistry of phosphole-containing hybrid calixphyrins: Promising macrocyclic P,N2,X-mixed donor ligands for designing reactive transition-metal complexes
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The syntheses, structures, and coordination chemistry of phosphole-containing hybrid calixphyrins (P,N2,X-hybrid calixphyrins) and the catalytic activities of their transition-metal complexes are reported. The 5,10-porphodimethene type 14π-P,(NH)2,X- and 16-P,N 2,X-hybrid calixphyrins (X = O, S, NH) are prepared via acid-promoted dehydrative condensation between a σ4-phosphatripyrrane and the corresponding 2,5-bis[hydroxy(phenyl)methyl]heteroles followed by DDQ oxidation. Both spectroscopic and crystallographic data of the hybrid calixphyrins have revealed that the conformation and size of the macrocyclic platforms as well as the oxidation state of the π-conjugated pyrrole-heterole-pyrrole (N-X-N) units vary considerably depending on the combination of heteroles. The σ3-P,(NH)2,S- and σ3-P,N2,S-hybrids react with Pd(OAc)2 and Pd(dba)2, respectively, to afford the same Pd(II)-P,N 2,S-hybrid complex, in which the calixphyrin platform is regarded as a dianionic ligand. In the complexation with [RhCl(CO)2]2 in dichloromethane, the σ3-P,N2,S-hybrid behaves as a neutral ligand to afford an ionic Rh(I)-P,N2,S-hybrid complex, whereas the σ3-P,N2,NH-hybrid behaves as an anionic ligand to produce Rh(III)-P,N3-hybrid complexes. In the latter reaction, it is likely that a neutral Rh(I)-P,N3-hybrid complex, generated as a highly nucleophilic intermediate, undergoes C-Cl bond activation of the solvent. The complexation of AuCl(SMe2) with the σ3-P,N2,X-hybrids (X = S, NH) leads to the formation of the corresponding Au(I)-monophosphine complexes. The spectral data and crystal structures of these metal complexes exhibit the hemilabile nature of the phosphole-containing hybrid calixphyrin platforms derived from the flexible phosphole unit and the redox active N-X-N units. The hybrid calixphyrin- palladium and -rhodium complexes catalyze the Heck reaction and hydrosilylations, respectively, implying that the metal center in the core is capable of activating the substrates under appropriate reaction conditions. The present results demonstrate the potential utility of the phosphole-containing hybrid calixphyrins as a new class of macrocyclic P,N2,X-mixed donor ligands for designing highly reactive transition-metal complexes.
- Matano, Yoshihiro,Miyajima, Tooru,Ochi, Noriaki,Nakabuchi, Takashi,Shiro, Motoo,Nakao, Yoshihide,Sakaki, Shigeyoshi,Imahori, Hiroshi
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p. 990 - 1002
(2008/09/21)
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- Benzimidazolium-pyrazole-palladium(II) complexes: New and efficient catalysts for Suzuki, Heck and Sonogashira reactions
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Three unsymmetrical benzimidazoliumpyrazole N-N ligands 2-(1-propylbenzimidazolylmethyl)-3,5-di-R-pyrazole (R=H, Me, t-Bu) have been conveniently prepared and structurally analyzed. The solid lattice packingof the R=Me compound at 223 K reveals one-dimensional "zig-zag" water chains stabilized by organic molecular channels through N...H-O and O-H...O bonding. These hybrid ligands add to palladium(II) to give high yields of air-stable complexes that are fully characterized by NMR, ESI, and X-ray single-crystal crystallography. They are active Suzuki catalysts at room temperature towards cross-couplingof unactivated aryl bromides and 5- or 6-membered heteroaryl bromides with arylboronic acids with turnover frequencies (TOF) reachingas high as 60,000 h-1. Their catalytic efficiency is significantly better than that of the C-N carbene-imidazole analogue. These catalysts are also active in Heck and Sonogashira cross-coupling reactions of aryl bromides giving the desired products in good yields. These results suggested that these Pd(II) complexes with N-based hybrid ligands are versatile and efficient catalysts for different types of cross-couplingreactio ns under aerobic conditions.
- Li, Fuwei,Hor, T. S. Andy
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experimental part
p. 2391 - 2400
(2009/10/08)
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- Efficient palladium(II) catalysis under air. Base-free oxidative heck reactions at room temperature or with microwave heating
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(Figure Presented) Scope and limitations of the base-free oxidative Heck reaction with arylboronic acids have been explored. Under our conditions, the dmphen-palladium(II)-catalyzed arylation proceeded with air or p-benzoquinone as reoxidants of palladium(0). We found that ambient temperature and mild aerobic conditions allow for the use of substrates sensitive to palladium(II)-catalyzed oxidation. Oxidative Heck couplings, employing different arylboronic acids, were smoothly and regioselectively conducted with both electron-rich and electron-poor olefins, providing high yields even with disubstituted butyl methacrylate, sensitive acrolein, and a vinylboronate ester. Controlled microwave processing was used to reduce reaction times from hours to minutes both in small scale and in 50 mmol scale batch processes.
- Lindh, Jonas,Enquist, Per-Anders,Pilotti, Ake,Nilsson, Peter,Larhed, Mats
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p. 7957 - 7962
(2008/02/13)
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- N-Phenylurea as an inexpensive and efficient ligand for Pd-catalyzed Heck and room-temperature Suzuki reactions
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N-Phenylurea was found to constitute a highly efficient, yet low-priced, phosphine-free ligand for the Pd-catalyzed Heck and room-temperature Suzuki reactions of aryl bromides and iodides with very high turnover numbers (ca. 103-104).
- Cui, Xin,Zhou, Yuan,Wang, Na,Liu, Lei,Guo, Qing-Xiang
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p. 163 - 167
(2007/10/03)
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- Pd(quinoline-8-carboxylate)2 as a low-priced, phosphine-free catalyst for heck and suzuki reactions
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(Chemical Equation Presented) N,O-Bidentate compounds were systematically evaluated as phosphine-free ligands for Pd-catalyzed C-C bond-formation reactions through kinetic measurements. Pd(quinoline-8-carboxylate)2 was identified as one of the most efficient, yet still low-priced, phosphine-free catalysts for Heck as well as Suzuki reactions of unactivated aryl bromides with high turnover numbers up to ca. 10,000.
- Cui, Xin,Li, Juan,Zhang, Zhi-Ping,Fu, Yao,Liu, Lei,Guo, Qing-Xiang
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p. 9342 - 9345
(2008/03/13)
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- Palladium(II) complexes containing a bulky pyridinyl N-heterocyclic carbene ligand: Preparation and reactivity
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Coordination chemistry of a pyridine imidazole-2-ylidene ligand (pyN ?C) with sterically hindered substituents toward palladium(II) metal ions has been investigated. The palladium carbene complex [(C-pyN ?C)Pd(η3-allyl)Cl] (3) is prepared via the transmetallation from the corresponding silver carbene complexes with [ClPd(η3-allyl)]2. Upon the abstraction of chloride, coordination of pyridinyl-nitrogen becomes feasible to form [C,N-(pyN ?C)Pd(η3-allyl)](BF4) (4). Ligand substitution reaction of 4 with triphenylphosphine results in the formation of [(C-pyN ?C)Pd(PPh3)(η3-allyl)](BF4)], which the pyridinyl-nitrogen donor is substituted by the phosphine. This palladium complex appears to be base sensitive. Treatment of 4 with t-butoxide causes the decomposition to yield the metal nano-particles. Furthermore, de-complexation of 4 takes place under hydrogen atmosphere to generate the carbene precursor, 1-(6-mesityl-2-picolyl)-3-mesitylimidazolium salt. Nevertheless, the palladium complex 4 shows good catalytic activity on the Suzuki-Miyaura and Mizoroki-Heck reactions.
- Wang, Chao-Yu,Liu, Yi-Hong,Peng, Shei-Ming,Chen, Jwu-Ting,Liu, Shiuh-Tzung
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p. 3976 - 3983
(2008/03/12)
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- Bronsted guanidine acid-base ionic liquids: Novel reaction media for the palladium-catalyzed heck reaction
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Bronsted acid-base ionic liquids (GILs) based on guanidine and acetic acid are efficient reaction media for palladium-catalyzed Heck reactions. They offer the advantages of high activity and reusability. GIL2 plays multiple roles in the reaction: it could act as solvent, as a strong base to facilitate β-hydride elimination, and as a ligand to stabilize activated Pd species.
- Li, Shenghai,Lin, Yingjie,Xie, Haibo,Zhang, Suobo,Xu, Jianing
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p. 391 - 394
(2007/10/03)
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- N,N-dimethyl-β-alanine as an inexpensive and efficient ligand for palladium-catalyzed Heck reaction
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N,N-Dimethyl-β-alanine was found to be a more powerful phosphine-free ligand than the previously reported ligand, N,N-dimethylglycine, in the Pd-catalyzed Heck reaction for a variety of aryl bromides, aryl iodides, and activated aryl chlorides with a practical turnover number of 103. Both kinetic and theoretical studies suggested that N,N-dimethyl-β-alanine led to faster oxidative addition of an aryl halide to Pd than N,N-dimethylglycine.
- Cui, Xin,Li, Zhe,Tao, Chuan-Zhou,Xu, Yu,Li, Juan,Liu, Lei,Guo, Qing-Xiang
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p. 2467 - 2470
(2007/10/03)
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- Ruthenium complex-catalysed Heck reactions of areneboronic acids; mechanism, synthesis and halide tolerance
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Ruthenium-arene complexes can act as efficient catalysts for the coupling of areneboronic acids with electrophilic alkenes. The chemoselectivity is completely different from palladium coupling, with full tolerance for halogen in the arene. NMR and ES-MS studies have been carried out to elucidate the reaction pathway.
- Farrington, Edward J.,Barnard, Christopher F. J.,Rowsell, Elizabeth,Brown, John M.
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p. 185 - 195
(2007/10/03)
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- Selenium-ligated palladium(II) complexes as highly active catalysts for carbon-carbon coupling reactions: The Heck reaction
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(Equation Presented) Three selenium-ligated Pd(II) complexes were readily synthesized and shown to be extremely active catalysts for the Heck reaction of various aryl bromides, including deactivated and heterocyclic ones. The catalytic activity of the selenide-based Pd(II) complexes not only rivals but vastly outperforms that of the corresponding phosphorus and sulfur analogues. Practical advantages of the selenium-based catalysts include their straightforward synthesis and high activity in the absence of any additives as well as the enhanced stability of the selenide ligands toward air oxidation.
- Yao, Qingwei,Kinney, Elizabeth P.,Zheng, Chong
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p. 2997 - 2999
(2007/10/03)
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- Synthesis of novel palladacycles and their application in heck and Suzuki reactions under aerobic conditions
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(Chemical Equation Presented) Design and synthesis of a novel family of furancarbothioamide-based palladacycles are reported herein. These palladacycles are thermally stable, not sensitive to air or moisture, and are applied effectively in the Heck reaction of aryl halides with terminal olefins and in the Suzuki reaction of aryl halides with arylboronic acids. These reactions were performed under aerobic conditions, leading to turnover numbers (TONs) up to 1 × 105.
- Xiong, Zhengchang,Wang, Nengdong,Dai, Mingji,Li, Ang,Chen, Jiahua,Yang, Zhen
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p. 3337 - 3340
(2007/10/03)
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- Ligand-free heck reaction: Pd(OAc)2 as an active catalyst revisited
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Palladium acetate was shown to be an extremely active catalyst for the Heck reaction of aryl bromides. Both the base and the solvent were found to have a fundamental influence on the efficiency of the reaction, with K 3PO4 and N,N-di
- Yao, Qingwei,Kinney, Elizabeth P.,Yang, Zhi
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p. 7528 - 7531
(2007/10/03)
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- Homeopathic ligand-free palladium as a catalyst in the heck reaction. A comparison with a palladacycle
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(Matrix presented) Ligand-free Pd(OAc)2 can be used as a catalyst in the Heck reaction of aryl bromides as long as the amount of catalyst is kept between 0.01 and 0.1 mol %. At higher concentrations palladium black forms and the reaction stops. The actual catalyst is monomeric. Palladacycles merely serve as a source of ligand-free palladium in Heck reactions of aryl bromides.
- de Vries, Andre H. M.,Mulders, Jan M. C. A.,Mommers, John H. M.,Henderickx, Huub J. W.,de Vries, Johannes G.
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p. 3285 - 3288
(2007/10/03)
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- Ruthenium-catalyzed oxidative heck reactions
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Aryl boronic acids can undergo a Heck-type reaction catalyzed by RuII in the presence of CuII, which serves as a reoxidant in each cycle (see scheme, step1).Compatibility with halide substituents offers attractive synthetic potential
- Farrington, Edward J.,Brown, John M.,Barnard,Rowsell
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p. 169 - 171
(2007/10/03)
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- A hexacarbene complex derived from 1,1′-methylenebis(4-butyl-1H-1,2,4-triazolium) diiodide. Synthesis, characterization and catalytic activity
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The synthesis and characterization of a hexacarbene complex (1) derived from 1,1′-methylenebis(4-butyl-1H-1,2,4-triazolium) diiodide are reported. The organic backbone was constructed prior to the introduction of metal atoms by reaction with palladium(II) acetate. The catalytic activity of 1 in a Heck reaction has been tested.
- Díez-Barra, Enrique,Guerra, Javier,Rodríguez-Curiel, René I,Merino, Sonia,Tejeda, Juan
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- First Application of Secondary Phosphines as Supporting Ligands for the Palladium-Catalyzed Heck Reaction: Efficient Activation of Aryl Chlorides
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Secondary dialkylphosphines were successfully used for the first time as efficient supporting ligands for the palladium-catalyzed Heck reaction of electron-rich and electron-poor aryl chlorides with olefins such as acrylate, ethylene, styrene, and n-butyl vinyl ether. The yields with HP(t-butyl)2 and HP(adamantyl)2 were comparable or better than those obtained with known systems of tertiary phosphines such as P(cyclohexyl)3 and P(t-butyl)3, especially at a catalyst loading of 1 mol %. In comparison with tertiary phosphines, the secondary phosphines have the advantage of being readily available at low cost on a technical scale, and are comparable with respect to handling and oxygen sensitivity.
- Schnyder, Anita,Aemmer, Thomas,Indolese, Adriano F.,Pittelkow, Ulrich,Studer, Martin
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p. 495 - 498
(2007/10/03)
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- A highly efficient palladium/imidazolium salt system for catalytic Heck reactions
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A palladium/imidazolium chloride system has been used to catalyze the Heck reaction. The combination of 2 mol% Pd(OAc)2 and 4 mol% IMes·HCl in the presence of Cs2CO3 as base has proven to be a highly efficient system in me
- Yang,Nolan
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p. 1539 - 1542
(2007/10/03)
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- Highly efficient C-C coupling reactions using metallated benzylphosphine complexes of palladium
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Phosphapalladacyclic complexes synthesised from orthobromobenzylphosphine ligands are effective catalysts for carbon-carbon bond forming reactions, exhibiting activity that compares with, and in several examples exceeds, that of existing systems.
- Gibson,Foster,Eastham,Tooze,Cole-Hamilton
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p. 779 - 780
(2007/10/03)
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- Process for preparing aromatic olefins by using palladaphosphacyclobutanes as catalysts
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The invention relates to a process for preparing monofunctional, bifunctional and polyfunctional aromatic olefins of the formula (I) by reacting haloaromatics of the formula (II) with olefins of the formula (III) wherein a palladium compound of the formul
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- Process for preparing aromatic olefins using palladacycle catalysis
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The invention relates to a process for preparing monofunctional, bifunctional or polyfunctional aromatic olefins of the formula (I) STR1 by reaction of haloaromatics of the formula (II) STR2 with olefins of the formula (III) STR3 , wherein a palladium com
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