- Sonogashira (Cu and amine free) and Suzuki coupling in air catalyzed: Via nanoparticles formed in situ from Pd(ii) complexes of chalcogenated Schiff bases of 1-naphthaldehyde and their reduced forms
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The reaction of 1-naphthaldehyde with 2-(phenylthio/seleno)ethylamine afforded air- and moisture-insensitive Schiff bases: C10H7-1-CHN-CH2CH2EPh (L1: E = S; L2: E = Se). Then, on treatment with NaOAc and Li2PdCl4, palladacycles, [Pd(L1-H/L2-H)Cl] (1/2) were formed at room temperature, in which L1/L2 are ligated as an unsymmetric (C-, N, E) pincer. The reduction of >CN bonds of L1 and L2 with sodium borohydride gave C10H7-1-CH2NH-CH2CH2EPh (L3: E = S; L4: E = Se). The reactions of L3/L4 at room temperature, similar to those of L1/L2, resulted in the formation of complex [Pd(L3/L4)Cl2] (3/4), in which the ligand is coordinated in a bidentate (N, E) mode. The yield of all the complexes was >85%. Characterization by HR-MS, 1H, 13C{1H} and 77Se{1H} NMR spectra of L1-L4 and their complexes 1-4 were performed. The structures of L1 and 1-4 were established with single-crystal X-ray diffraction. In all the complexes, the geometry of palladium was distorted square planar. The Pd-S bond distances in 1 and 3 were 2.426(12) and 2.259(2) ?, respectively, whereas Pd-Se bond lengths (?) were 2.523(11) (2) and 2.369(10) (4) ?. The catalytic activities of 1-4 were explored for copper- and amine-free Sonogashira and Suzuki-Miyaura coupling (SMC) of aryl halides under aerobic conditions. The amount of catalyst required for achieving good conversion was 0.01 and 0.05 mol% for SMC and Sonogashira coupling, respectively. The conversion of some substrates reached a maximum in 1 and 2 h for Sonogashira coupling and SMC, respectively. The palladacycles as catalysts gave good conversion efficiency. The generation of palladium-containing nanoparticles (NPs) during both coupling reactions was observed. These were isolated and HR-TEM studies were performed on them and revealed their size as ~2-7 nm. The SEM-EDX analysis indicated the presence of organochalcogen ligands or their fragments in the samples. They independently catalyzed both reactions. Therefore, the role of 1-4 in catalysis undoubtedly exists. For Sonogashira coupling, the formation and role of such Pd-based NPs under aerobic conditions were observed for the first time. The complexes 1-4 showed the potential for reuse, as in the eighth cycle, conversion dropped by only 20%.
- Bhaskar, Renu,Sharma, Alpesh K.,Yadav, Manoj K.,Singh, Ajai K.
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- Silica-anchored proline-copper(I) as an efficient and recyclable catalyst for the Sonogashira reaction
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A novel silica-anchored proline-copper(I) organic-inorganic hybrid material as an efficient catalyst for the Sonogashira reaction was developed. Terminal alkynes were reacted with aryl iodides and bromides smoothly in the presence of a proline-functionalized silica-anchored copper(I) catalyst in DMF to afford the corresponding cross-coupling products in good to excellent yields. Furthermore, silica-anchored proline-copper(I) catalyst was recovered and recycled by a simple filtration of the reaction solution and reused for six times without significant decreases in activity. Georg Thieme Verlag Stuttgart.
- Wang, Zuli,Wang, Lei,Li, Pinhua
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- A mesoionic bis(Py-tzNHC) palladium(II) complex catalyses "green" Sonogashira reaction through an unprecedented mechanism
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A novel bis(pyridyl-functionalized 1,2,3-triazol-5-ylidene)-palladium(ii) complex [Pd(Py-tzNHC)2]2+ catalyses the copper-, amine-, phosphine-, and additive-free aerobic Sonogashira alkynylation of (hetero)aryl bromides in water as the only reaction solvent. The catalysis proceeds along two connected Pd-cycles with homogeneous bis-carbene Pd0 and PdII species, as demonstrated by electrospray ionization mass spectrometry.
- Gazvoda, Martin,Virant, Miha,Pevec, Andrej,Urankar, Damijana,Bolje, Aljo?a,Ko?evar, Marijan,Ko?mrlj, Janez
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- Synthesis and characterization of a polymer-anchored palladium(II) Schiff base complex and its catalytic efficiency in phosphine-free Sonogashira coupling reactions
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A polymer-anchored Pd(II) Schiff base complex has been synthesized by reacting a polymeric amine with 2-pyridinecarboxaldehyde to get the polymer-anchored Schiff base, which was then reacted with palladium acetate. The catalyst was characterized by physicochemical and spectroscopic methods. It shows excellent catalytic activity in the Sonogashira coupling of phenylacetylene with aryl halides using triethylamine as a base and copper iodide as a co-catalyst in water under open air at 70 °C. We have also studied the effects of base and solvent on the coupling reaction. Sonogashira reactions of phenylacetylene with a variety of functionalized aryl halides were performed under the optimized reaction conditions. This catalyst gives excellent yields without the use of phosphine ligands. Further experiments showed that the catalyst can be used five times without much loss in the catalytic activity. Springer Science+Business Media B.V. 2010.
- Islam,Mondal, Sanchita,Roy, Anupam Singha,Mondal, Paramita,Mobarak, Manir,Hossain, Dildar,Pandit, Palash
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- Synthesis and characterization of nickel inverse 9-metallacrown-3, palladium-silver, and dinuclear platinum complexes containing pyrazole-functionalized NHC ligands
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Three metallacrown nickel complexes [Ni3(μ-OH)(L1) 3](PF6)2 (1, L1 = 3-((N-methylimidazolylidenyl) methyl)-5-methylpyrazolate), [Ni3(μ-OH)(L2)3](PF 6)2 (2, L2 = 3-((N-mesitylimidazolylidenyl)methyl)-5- methylpyrazolate), and [Ni3(μ-OH)(L3)3](PF 6)2 (3, L3 = 3-((N-pyrimidin-2-ylimidazolylidenyl)methyl)- 5-methylpyrazolate) were obtained by the reactions of corresponding silver-NHC complexes with Raney nickel powder at 45 °C. The same reaction at 80 °C afforded [Ni3(L2)4](PF6)2 (4). The carbene-transfer reaction of the silver-carbene complex with [(η3-C3H5)PdCl]2 yielded the heterotrimetallic complex [AgPd2(η3-C 3H5)2(L2)2](PF6) (5), whereas the carbene-transfer reaction with Pt(cod)Cl2 gave [Pt 2(L3)2](PF6)2 (6). All of these complexes have been fully characterized by ESI-MS, NMR spectroscopy, and elemental analysis. The molecular structures of 1-6 were also studied by X-ray diffraction analysis. In 1-3, three nickel centers are bridged together by three pyrazole-NHC ligands and a hydroxide group, forming a 9-metallacrown-3 topology. Complex 4 is paramagnetic, consisting of two square-planar nickel(II) ions and one tetrahedral nickel ion in which three Ni ions are bridged by four pyrazolate units. In the mixed Pd-Ag complex 5, two palladium and one silver centers are bridged by two pyrazole-NHC ligands. Complex 5 showed good catalytic activity in the Sonogashira coupling reaction of aryl bromides and phenylacetylene under mild conditions typically catalyzed by Pd-Cu systems.
- Chen, Chao,Qiu, Huayu,Chen, Wanzhi
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- Cyclization of Diaryl(hetaryl)alkynes under Selenobromination Conditions: Regioselectivity and Mechanistic Studies
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The cyclization of substituted diaryl(hetaryl)alkynes with in-situ-prepared SeBr4 has been achieved. The use of an alkene additive as a bromine scavenger gives simple access to functionalized benzo[b]selenophene and selenophenothiophene derivatives from commercially available or easily accessible starting materials. The reactions can be performed in air without the use of moisture-sensitive reagents, dry solvents, or an inert atmosphere. Mechanistic studies confirmed a regioselective anti 1,2-addition in the selenobromination step, and a subsequent electrophilic substitution in the aromatic ring to complete the cyclization. The cyclization of substituted diaryl(hetaryl)alkynes with in-situ-prepared SeBr4 has been achieved. The use of an alkene additive as a bromine scavenger gives simple access to functionalized benzo[b]selenophene and selenophenothiophene derivatives from commercially available or easily accessible starting materials.
- Paegle, Edgars,Belyakov, Sergey,Petrova, Marina,Liepinsh, Edvards,Arsenyan, Pavel
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- Recyclable and reusable NiCl2(PPh3)2/CuI/PEG-400/H2O system for the sonogashira coupling reaction of aryl iodides with alkynes
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A stable and highly efficient NiCl2(PPh3)2/CuI/PEG-400/H2O catalytic system for the Sonogashira reaction has been developed. In the presence of NiCl2(PPh3)2 and CuI, the coupling reaction of aryl iodides with terminal alkynes was carried out smoothly in a mixture of poly(ethylene glycol) (PEG-400) and water at 100C with K2CO3 as base to afford a variety of arylacetylenes in good to excellent yields. The isolation of the products was readily performed by extraction with petroleum ether, and the NiCl2(PPh3)2/CuI/PEG-400/H2O system could be easily recycled and reused six times without significant loss of catalytic activity. Our system not only avoids the use of easily volatile organic solvents but also solves the basic problem of catalyst reuse.
- Wei, Ting,Zhang, Tingli,Huang, Bin,Tuo, Yuxin,Cai, Mingzhong
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- N-heterocyclic carbene adducts of cyclopalladated ferrocenylchloropyrimidine: Synthesis, structural characterization and application in the Sonogashira reaction
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Three N-heterocyclic carbene (NHC) adducts of cyclopalladated ferrocenylchloropyrimidine, 2-4 [PdCl{[(n5-C5H 5)]Fe[(n5-C5H3)-N2C 4H2-Cl]}(NHCs)] have been prepared by reaction of the chloride-bridged palladacyclic dimer 1 [PdCl{[(n5-C5H 5)]Fe[(n5-C5H3)-N2C 4H2-Cl]}]2 with the corresponding imidazolium salts. These complexes were characterized by elemental analysis, IR, ESI-MS and NMR. The use of these complexes as catalysts for the Sonogashira reaction was examined. Complex 4 proved to be an efficient catalyst for the Sonogashira reaction of aryl bromides and some activated aryl chlorides under copperand amine-free conditions. Typically, using 0.1-2 mol % of catalyst in the presence of 1.5 equivalents of CsOAc as base in dimethylacetamide at 120 °C provided coupling products in good yields. Springer Science+Business Media B.V. 2012.
- Xu, Chen,Lou, Xin-Hua,Wang, Zhi-Qiang,Fu, Wei-Jun
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- Blue fluorescent 4a-aza-4b-boraphenanthrenes
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Figure presented Phenanthrene analogues with internalized B-N moieties were found to afford blue light emission with good quantum efficiencies, whereas the isomeric species with peripheral B-N moieties displayed only UV emission behavior, like the all-carbon framework.
- Bosdet, Michael J. D.,Jaska, Cory A.,Piers, Warren E.,Sorensen, Ted S.,Parvez, Masood
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- Palladium particles from oxime-derived palladacycle supported on Fe3O4/oleic acid as a catalyst for the copper-free Sonogashira cross-coupling reaction
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An oxime-derived palladacycle was synthesized using 4-bromobenzoxime and pyridine in CHCl3, and characterized by FT-IR and 1H NMR spectroscopy. This Pd complex was supported on Fe3O4/oleic acid and shown to be an efficient catalyst for the copper-free Sonogashira cross-coupling reaction of various aryl halides with phenylacetylene in air and in ethanol or mixed aqueous medium. The oxime-derived palladacycle gave highly active palladium nanoparticles for the organic synthesis. The coupling products were obtained in high yields with low Pd loading and the heterogeneous catalyst can be separated by an external magnet and reused six times without loss of its activity. The characterization of the catalyst was carried out by XRD, SEM and TEM. Both TEM and XRD revealed that the palladium nanoparticles were well dispersed with diameters from 5 to 10 nm and average size 9.97 nm.
- Karami, Kazem,Najvani, Samaneh Dehghani,Naeini, Nasrin Haghighat,Hervés, Pablo
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- Mesoporous Carbon Supporting Pd (0) as a Highly Efficient and Stable Catalyst for Sonogashira Reaction in Aqueous Media
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Abstract: In this study, palladium (0) nanoparticle supported on mesoporous carbon (Pd/MPC) is prepared by impregnation and H2 reduction. Characterization by XRD, XPS and TEM reveals the mesoporous structure and a high dispersion of palladium nanoparticles (about 4.8?nm) in the mesopores. The catalyst has excellent catalytic activity and stability for Sonogashira reactions of aryl halide (–I, –Br) in aqueous solution. It is noteworthy that Sonogashira reactions of aryl halide (–Cl) can occur by using the novel Pd/MPC catalyst. Meanwhile, the catalyst can be recovered and reused without loss of efficiency until the fifth cycle in water. The fresh catalyst would be of major significance for industrial applications. Graphical Abstract: [Figure not available: see fulltext.]
- Wang, Peng,Wang, Guang-Yu,Qiao, Wen-Long,Feng, Yi-Si
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- Post-synthetic modified MOF for Sonogashira cross-coupling and Knoevenagel condensation reactions
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A new heterogeneous NHC catalyst (1-Pd) was obtained by the post-synthetic modification of an azolium-containing metal-organic framework (1) which was synthesized by solvothermal reaction of 1,3-bis(4-carboxyphenyl)imidazolium chloride (H2L+Cl?) and Zn(NO3)2·6H2O. This new material, 1-Pd, was characterized by PXRD, TGA, SEM, TEM, 1H and 13C NMR, FTIR and XPS measurements. This catalyst exhibited an excellent activity for both Sonogashira cross-coupling and Knoevenagel condensation reaction retaining its catalytic and uniform distribution of the active sites, palladium (II) anchored on N-heterocyclic carbene (NHC-Pd(II)), for at least four cycles without losing its structural integrity.
- Ezugwu, Chizoba I.,Mousavi, Bibimaryam,Asraf, Md. Ali,Luo, Zhixiong,Verpoort, Francis
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- Copper- and base-free Sonogashira-type cross-coupling reaction of triarylantimony dicarboxylates with terminal alkynes under an aerobic condition
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A simple copper- and base-free palladium-catalyzed Sonogashira-type cross-coupling by the use of triarylantimony dicarboxylates is described. Reaction of triarylantimony diacetates with terminal alkynes in the presence of 1 mol % of PdCl2(PPhs
- Wang, Xuan,Qin, Weiwei,Kakusawa, Naoki,Yasuike, Shuji,Kurita, Jyoji
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- Copper(i) catalyzed Sonogashira reactions promoted by monobenzyl nicotinium chloride, a N-donor quaternary ammonium salt
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A novel and effective catalytic system using monobenzylnicotinium chloride combined with copper(i) chloride was employed for the first time in Sonogashira cross-coupling reactions of phenylacetylene with various aryl halides. The goal was to use an efficient green media by using copper instead of palladium in metal-catalyzed coupling reactions. Monobenzyl nicotinium chloride, a quaternary ammonium salt containing a coordinating centre, plays an important role in this catalytic system and increases the efficiency of Cu(i) species during the reaction. A number of internal alkynes were produced in moderate to excellent yields in short reaction times in DMF at 135-140 °C. The efficiency of this catalytic system was compared with the copper-based catalyst obtained from dibenzylnicotinium chloride which has no N-donor active site, wherein lower activity was observed due to lack of a coordination site.
- Hajipour, Abdol Reza,Boostani, Elaheh,Mohammadsaleh, Fatemeh
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- Influence of pendent alkyl chains on Heck and Sonogashira C-C coupling catalyzed with palladium(II) complexes of selenated Schiff bases having liquid crystalline properties
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The effect of pendent alkyl chain lengths on Heck and Sonogashira coupling has been investigated for the first time using air and moisture insensitive complexes, [PdLCl] (1-4), of selenated Schiff bases (L = L1-L4), differing in length and number of pendent alkyl chain(s) and behaving as a (Se, N, O -) type of ligand. Differential scanning calorimetric (DSC) and polarized optical microscopic (POM) investigations show liquid crystalline nature of L1 and L2, which have one pendent alkyl chain of size C18 and C10 respectively. The yields of coupled products in catalytic Heck and Sonogashira coupling reactions were found good when amount of 1-4 used for them was 1.0 and 0.5 mol% respectively. The catalytic efficiency decreases with alkyl chain length of pendent arm of ligand for Heck coupling but remains unaffected in case of Sonogashira coupling. The in situ generation of palladium nanoparticles (NPs) protected with organoselenium species occurs in the case of Heck coupling. The length of pendent alkyl chain appears to control the dispersion and composition of these NPs and consequently the catalytic efficiency for Heck coupling. The black residues formed in the case of Sonogashira coupling catalyzed with 1 and 4 were found to have small fraction of NPs and a large proportion of big size aggregates. Their compositions for both the catalysts have been found nearly the same and due to predominance of aggregates, the efficiency remains almost unchanged on varying length of pendent alkyl chain. The two phase test for Heck coupling indicates that catalysis is largely heterogeneous.
- Rao, Gyandshwar Kumar,Kumar, Arun,Singh, Mahabir Pratap,Kumar, Ajay,Biradar, Ashok Manikrao,Singh, Ajai K.
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- Copper-free PdCl2/PPh3-catalyzed Sonogashira coupling reaction of aryl bromides with terminal alkynes in water
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A simple, copper-free and efficient catalytic system for the Sonogashira coupling reaction of aryl bromides with terminal alkynes in pure water has been developed. The use of PdCl2/PPh3 in the presence of pyrrolidine allows the coupling reaction to proceed at 120 °C in moderate to excellent yields.
- Guan, Jin Tao,Weng, Tan Qing,Yu, Guang-Ao,Liu, Sheng Hua
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- Palladium-catalyzed deacetonative coupling of aryl propargylic alcohols with aryl chlorides in water
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A highly efficient and green process for palladium-catalyzed deacetonative coupling of aryl propargylic alcohols with aryl chlorides has been developed. The reaction occurs smoothly in neat water with 2 mol% PdCl2 as catalyst, and various synthetically useful functional groups, including ether, aldehyde, ketone, and heterocyclics, are well tolerated. Moreover, the reaction could proceed through a consecutive Sonogashira/deacetonative process using 2-methyl-3-butyn-2-ol and aryl chlorides as coupling partners, affording the symmetric alkynes in good yields.
- Chang, Feng,Liu, Yanping
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- Sonogashira coupling using PdEnCat: A copper-, phosphine-, amine-and microwave-free alternative to the preparation of arylalkynes
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Sonogashira coupling of iodo-and bromoarenes and acetylenes using PdEnCat 30 in a phosphine-, copper-, amine-, and microwave-free system was developed, which allows for the preparation of a modulator of glutamate receptor mGluR5. Copyright
- Barros, Jose C.,Yaunner, Ricardo S.,De Souza, Andrea Luzia F.,Da Silva, Joaquim F. M.,Antunes, Octavio A. C.
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- Towards to the trans-bromination of 2-styrylpyridine with a palladacycle intermediary and structure analysis for trans-1,2-dibromo-2-styrylpyridine
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The simple halogenation of alkynes in conventional organic reactions gives a blend of cis and trans isomers. It is proposed then, a synthesis of stereospecific halogenation of alkynes in trans position, using palladacycle as intermediaries. The recrystallization of the compound obtained by bromination of 2-Styrylpyridine, with cyclepalladium intermediary results in a single crystal, which is subjected to X-ray diffraction. The crystal packing is established through weak interactions of three types. The first one is of the type π × π interactions, from symmetry operation, between the centroids. The second one is of the type C-X?π interactions. And the last type is an anomalous intermolecular interaction between halogens, C-X?X-C, with bond distances smaller than the sum of the van der Waals radii. The conformation on the C=C bond is trans and the dihedral angle between the aromatic rings is (with esd approximate) 18.1(3)°.
- Mafud, Ana Carolina,Gambardella, Maria Teresa Do Prado,Caires, Antonio Carlos Fávero
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- Mechanistic insights into copper-catalyzed sonogashira-hagihara-type cross-coupling reactions: Sub-mol % catalyst loadings and ligand effects
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An efficient catalytic system for Sonogashira-Hagihara-type reactions displaying ligand acceleration in the copper-catalyzed formation of C(sp 2)-C(sp) bonds is described. The structure of the ligand plays a key role for the coupling efficiency. Various copper sources show excellent catalytic activity, even in sub-mol % quantities. A wide variety of substituents is tolerated in the substrates. Mechanistic details have been revealed by kinetic measurements and DFT calculations. Just a pinch of copper! An efficient system for the formation of C(sp2)-C(sp) bonds has been developed. In sub-mol % quantities various copper sources showed excellent catalytic activity. Different combinations of aryl(hetero) iodides and terminal aryl(hetero) alkynes were applied, leading to the desired products in moderate to excellent yields (see scheme; DMEDA=N,N′-dimethylethylenediamine). Mechanistic details of this process have been revealed by kinetic measurements and DFT calculations. Copyright
- Zou, Liang-Hua,Johansson, Adam Johannes,Zuidema, Erik,Bolm, Carsten
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- Pd-grafted porous metal-organic framework material as an efficient and reusable heterogeneous catalyst for C-C coupling reactions in water
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Palladium nanoparticles (Pd NPs) have been grafted at the surfaces of a Co-containing metal-organic framework material MCoS-1. The Pd NPs grafted material Pd(0)/MCoS-1 has been characterized by HR TEM, XPS and EPR spectroscopic analyses. Pd(0)/MCoS-1 showed excellent catalytic activities in Suzuki-Miyaura cross-coupling reaction for the synthesis of a diverse range of biaryl organics in water. Sonogashira cross-coupling between terminal alkynes and aryl halides has also been carried out over this Pd-nanocatalyst in water without the addition of any Cu co-catalyst. In both reactions the catalyst is easily recoverable and can be reused for several times without appreciable loss of catalytic activity. No evidence of the leaching of Pd from the catalyst during the course of reaction has been observed, suggesting true heterogeneity in our catalytic systems.
- Roy, Anupam Singha,Mondal, John,Banerjee, Biplab,Mondal, Paramita,Bhaumik, Asim,Islam, Sk. Manirul
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- An N-heterocyclic carbene based MOF catalyst for Sonogashira cross-coupling reaction
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The post-synthetic modification of azolium containing MOFs generated a new heterogeneous N-heterocyclic carbene catalyst (1-Pd), which is very active for Sonogashira cross coupling reaction.
- Ezugwu, Chizoba I.,Mousavi, Bibimaryam,Asrafa, Md. Ali,Mehta, Akshay,Vardhan, Harsh,Verpoort, Francis
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- Sonogashira cross-coupling reactions with heteroaryl halides in the presence of a tetraphosphine-palladium catalyst
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Heteroaryl halides undergoes cross-couplings with alkynes in good yields in the presence of [PdCl(C3H5)]2/cis,cis,cis-1,2, 3,4-tetrakis(diphenylphosphinomethyl)cyclopentane as catalyst. A variety of heteroaryl halides such as pyridines, quinolines, a pyrimidine, an indole, a thiophene, or a thiazole have been used successfully. The reaction also tolerates several alkynes such as phenylacetylene and a range of alk-1-ynols. Furthermore, this catalyst can be used at low loading with some substrates.
- Feuerstein, Marie,Doucet, Henri,Santelli, Maurice
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- Application of recoverable nanosized palladium(0) catalyst in Sonogashira reaction
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In the absence of ligand, copper and amine, a recoverable nanoparticle palladium(0) catalyzed Sonogashira reaction of aryl iodides and bromides with terminal alkynes was developed. The protocol involved the use of an environmental-friendly reaction system with ethanol as the solvent, potassium carbonate as a base, and poly(vinylpyrrolidone) (PVP) supported nanosized palladium metal colloids as the catalyst. The palladium metal was recovered and recycled by a simple decantation of the reaction solution and used for eight consecutive trials without significant loss of its reactivity.
- Li, Pinhua,Wang, Lei,Li, Hongji
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- Palladium nanoparticles immobilized on magnetic methionine-functionalized chitosan: A versatile catalyst for Suzuki and copper-free Sonogashira reactions of aryl halides at room temperature in water as only solvent
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The preparation of an efficient heterogeneous catalyst system based on the immobilization of palladium nanoparticles on a magnetic nanoparticle core (ImmPd(0)-MNPs) is described. The new catalytic system was characterized using transmission and scanning electron microscopies, X-ray diffraction, energy-dispersive X-ray and Fourier transform infrared spectroscopies, thermogravimetric analysis, vibrating sample magnetometry and inductively coupled plasma analysis. We have demonstrated that ImmPd(0)-MNPs is an efficient and reusable catalyst for the Suzuki–Miyaura and Sonogashira coupling reactions of various types of aryl halides in water as a green and environmentally acceptable solvent. Moreover, the reactions were carried out efficiently at room temperature. The catalyst was easily separated using an external magnet from the reaction mixture and recycled ten times without significant loss of activity.
- Hajipour, Abdol R.,Tavangar-Rizi, Zeinab
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- Pincer-type di(1,2,4-triazolin-5-ylidene)Pd(ii) complexes and their catalytic activities towards Cu- and amine-free Sonogashira reaction
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Pd(ii) complexes [PdBr(A-κ3CNC)]Br (1) and [PdBr(B-κ3CNC)]Br (2) with new CNC pincer-type ligands derived from 1,2,4-triazolin-5-ylidenes have been synthesized and characterized by multinuclei NMR spectroscopies, ESI mass spectrometry and X-ray diffraction analysis. The more soluble complex 1 proved to be an efficient pre-catalyst in copper- and amine-free Sonogashira reaction with high turnover numbers. The potential for recycling of the catalyst was also demonstrated. The Royal Society of Chemistry 2013.
- Huynh, Han Vinh,Lee, Chen-Shiang
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- Substituent effect of diimino-palladium (II) pincer complexes on the catalysis of Sonogashira coupling reaction
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Three NCN diimine ligands 4-6 were synthesized after condensation of isophthalaldehydes 1-3 and anilines. Treatment of 4-6 with Pd2(dba)3 in toluene resulted in the corresponding PdII-NCN-But (7), PdII-NCN-H (8) and PdII-NCN-NO2 (9) pincer complexes, respectively with high yields. Palladium pincers 7-9 and their precursors 4-6 were fully characterized by elemental analysis, IR, 1H NMR and 13C NMR spectroscopy. The molecular structures of 7b and 9b were also determined by X-ray single crystal diffraction. Sonogashira coupling of phenyl acetylene and 3-nitrobenzene catalyzed by 7-9 show that 9 exhibits the highest catalytic activity, suggesting that the electron withdrawing groups at the position-4 of palladium atom in palladium pincers will enhance their catalytic activity.
- Zhang, Jin-Hua,Li, Ping,Hu, Wen-Ping,Wang, Hong-Xing
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- Synthesis and characterization of functionalized titania-supported Pd catalyst deriving from new orthopalladated complex of benzophenone imine: Catalytic activity in the copper-free Sonogashira cross-coupling reactions at low palladium loadings
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The present work describes the preparation of organically modified TiO2-supported Pd catalyst originated from the new benzophenone imine-derived CN-palladacycle. The heterogeneous organic-inorganic hybrid catalyst system has been characterized by FT-IR, XRD, SEM, EDX, TEM and XPS techniques and exhibited good catalytic activity in the Sonogashira cross-coupling reactions of phenylacetylene with aryl halides under copper-, amine- and phosphine-free conditions, in conjunction with the ultra low catalyst Pd-loading. Significantly, the heterogeneous Pd catalyst allowed the reaction of phenylacetylene with aryl iodides to improve in excellent yields under very mild conditions using green solvent. Finally, the reusability of the supported Pd-complex was investigated by multiple reuses of the supported catalyst in subsequent Sonogashira cross-couplings.
- Karami, Kazem,Abedanzadeh, Sedigheh,Hervés, Pablo
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- Cyclopalladated ferrocenylimines: efficient catalysts for homocoupling and Sonogashira reaction of terminal alkynes
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A novel pathway for homocoupling of terminal alkynes has been described using cyclopalladated ferrocenylimine 1 or 2/CuI as catalyst in the air. This catalytic system could tolerate several functional groups. The palladacycle 2 in the presence of n-Bu4NBr as an additive could be applied to Sonogashira cross-coupling reaction of aryl iodides, aryl bromides, and some activated aryl chlorides with terminal alkynes under amine- and copper-free conditions, mostly to give moderate to excellent yields.
- Yang, Fan,Cui, Xiuling,Li, Ya-nan,Zhang, Jinli,Ren, Ge-rui,Wu, Yangjie
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- Copper(I) complex covalently anchored on graphene oxide as an efficient and recyclable catalyst for Sonogashira reaction
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In this study, the organosilane-functionalized graphene oxide as a stabilizer was prepared by a facile one-step silylation approach. [Cu(PPh3)3Cl] complex was successfully immobilized onto the graphene oxide surface through coordination interaction with organosilane ligand spacers. The supported catalyst showed enhanced catalytic performance toward Sonogashira reaction of aryl halides with phenylacetylene in water solvent compared with the homogeneous analogues, and it could be readily recycled and reused several times without discernible loss of its activity.
- Fath, Roghayeh Hashemi,Hoseini, S. Jafar
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- Sonogashira couplings catalyzed by collaborative (N-heterocyclic carbene)-copper and -palladium complexes
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A general protocol for the Sonogashira reaction using a 100:1 combination of (N-heterocyclic carbene)-Cu and (N-heterocyclic carbene)-Pd complexes is presented. Catalyst loadings of 1 mol % (NHC)-Cu and 0.01 mol % (NHC)-Pd allow for the coupling of aryl bromides and aryl alkynes, in air and in a non-anhydrous solvent, in high yields.
- Gallop, Christopher W. D.,Chen, Ming-Tsz,Navarro, Oscar
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- Electronic Structure and UV Absorption Spectra of 2-Pyridylacetylenes: An Intramolecular Orbital Interaction between the n Orbital on the Nitrogen Atom of the Pyridine Ring and the In-plane π Orbital of the Ethynylene Group
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The UV absorption spectra of some pyridylacetylenes were measured in various media at room temperature and 77 K, and the origin of the electronic absorption bands of these compounds was clarified compared with the results of MO calculations. For instance, it has been found that the 304.6, 271.7, 221, and 216 nm bands of l-(2-pyridyl)-2-phenylethyne in cyclohexane can be assigned to the calculated S1← S0, S9←S0, S9←S0, and S10←S0 transitions, respectively, in which the observed 271.7 nm band (S5←S0) is ascribed as a new type transition from the n orbital on the aza-nitrogen atom of the pyridine ring to the in-plane π* orbital on the sp-carbon atoms of the ethynylene group. Furthermore, it is revealed that the observed 259.6 nm band of l,2-di(2-pyridyl)ethyne (D2PE) can also be assigned to a new type of transition caused by weak interactions between the n orbitals and the in-plane π orbital of the ethynylene group. This result indicates that two n orbitals of the terminal pyridine rings of D2PE may interact with each other via the central in-plane π orbital.
- Okubo, Jun,Shinozaki, Hiraku,Koitabashi, Toshiyuki,Yomura, Ryo
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- Ligand-free Fe-Cu cocatalyzed cross-coupling of terminal alkynes with aryl halides
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Copper ferrite-nanoparticle-mediated cross-coupling of terminal alkynes with aryl halides under ligand-free conditions was demonstrated. The magnetic nature of the copper ferrite nanoparticles was exploited for easy and quantitative separation of the catalyst. Leaching of Fe and Cu to the reaction medium was found to be within permissible limit and the activity of the catalyst was almost unaltered up to three consecutive cycles.
- Panda, Niranjan,Jena, Ashis Kumar,Mohapatra, Sasmita
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- Polystyrene-anchored palladium(II) schiff base complex: A reusable catalyst for phosphine-free and copper-free sonogashira cross-coupling reaction in aqueous medium
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A novel polystyrene-supported palladium(II) complex, an excellent and recyclable catalyst, was synthesized for Sonogashira reactions. The present complex shows high catalytic activity for Sonogashira cross-coupling reaction of aryl halides with phenylacetylene under phosphine-free and copper-free reaction conditions in aqueous (DMF-H2O)medium.The catalyst could be reused for at least six reaction cycles with almost unchanged catalytic properties. Taylor & Francis Group, LLC.
- Islam, Manirul,Mondal,Roy, A. Singha,Tuhina,Mondal,Hossain
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- A novel silver iodide catalyzed sonogashira coupling reaction
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A novel and efficient Ag-catalyzed Sonogashira coupling reaction has been developed. Terminal alkynes couple with aryl iodides and aryl bromides in the presence of silver iodide, tri-phenylphosphine and potassium carbonate to afford the corresponding cross-coupling products in high yields. Georg Thieme Verlag Stuttgart.
- Li, Pinhua,Wang, Lei
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- Synthesis of thiospinel CuCo2S4 and CuCo2S4/reduced-graphene oxide nanohybrids as highly effective catalysts for the Sonogashira reaction
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Formation of a carbon-carbon bond using the transition metal catalyzed Sonogashira coupling reaction is an indispensable tool in synthetic organic chemistry. Initially complexes of Pd were used as catalysts, however advances in catalyst design fuelled the development of Cu catalysts, which are cheaper and more environmentally benign than complexes of Pd. This is the first paper that reports the application of thiospinels in the Sonogashira reaction. Thiospinel CuCo2S4 and CuCo2S4/reduced-graphene oxide (RGO) nanohybrids were first synthesized through a simple solvothermal approach. Our studies show that all of these nanohybrids are suitable for the Sonogashira reaction in water at room temperature. Compared to classical reactions, this method consistently has the advantages of a green solvent, short reaction times, low catalyst loading, high yields and reusability of the catalysts and a facile method for the preparation of the catalysts. The CuCo2S4 and CuCo2S4/RGO nanohybrids showed highly improved catalytic activity towards aryl chloride derivatives compared to other catalysts that have been reported.
- Hashemi Fath, Roghayeh,Hoseini, S. Jafar
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- Copper(0) nanoparticle catalyzed Z-Selective Transfer Semihydrogenation of Internal Alkynes
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The use of copper(0) nanoparticles in the transfer semihydrogenation of alkynes has been investigated as a lead-free alternative to Lindlar catalysts. A stereo-selective methodology for the hydrogenation of internal alkynes to the corresponding (Z)-alkenes in high isolated yields (86% average) has been developed. This green and sustainable transfer hydrogenation protocol relies on non-noble copper nanoparticles for reduction of both electron-rich and electron-deficient, aliphatic-substituted and aromatic- substituted internal alkynes. Polyols, such as ethylene glycol and glycerol, have been proven to act as hydrogen sources, and excellent stereo- and chemoselectivity have been observed. Enabling technologies, such as microwave and ultrasound irradiation are shown to enhance heat and mass transfer, whether used alone or in combination, resulting in a decrease in reaction time from hours to minutes. (Figure presented.).
- Moran, Maria Jesus,Martina, Katia,Bieliunas, Vidmantas,Baricco, Francesca,Tagliapietra, Silvia,Berlier, Gloria,De Borggraeve, Wim M.,Cravotto, Giancarlo
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supporting information
p. 2850 - 2860
(2021/05/06)
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- Xantphos-coordinated palladium dithiolates: Highly efficient catalyst for decarboxylative Sonogashira reaction into corresponding alkynes
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This work reports Xantphos-coordinated palladium dithiolate complexes as catalysts for decarboxylative Sonogashira coupling reaction of phenyl propiolic acid and 2-butynoic acid with various iodoarenes. These palladium aryl dithiolate complexes were synthesized and characterized by 1H and 31P nuclear magnetic resonance (NMR) spectroscopy, melting point, and elemental analysis (CHNS). Synthetic utility for the reported protocol is explored for the effect of various functional groups on the yield of corresponding heteroaryl alkynes. The current protocol showed excellent catalytic activity towards decarboxylative alkynylation reaction with high turn-over number (TON) up to 105 and turn-over frequency (TOF) up to 104 h?1. The catalyst could be recycled up to six recycles without losing its catalytic activity. The in situ generation of palladium nanoparticles (PdNPs) was observed after the third recycle, and the amount was significant after the sixth recycle, which were confirmed and characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray (EDX) analysis and high-resolution transmission electron microscopy (HR-TEM). The catalytic activity of the reaction is attributed to the formation of PdNPs.
- Lokolkar, Manjunath S.,Mane, Pravin A.,Dey, Sandip,Bhanage, Bhalchandra M.
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- A facile protocol for copper-free palladium-catalyzed Sonogashira coupling in aqueous media
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The combination of a readily available palladium catalyst and an eco-friendly basic aqueous solution of room-temperature ionic liquid, choline hydroxide (ChOH), was used in a facile protocol alternative to the Sonogashira coupling reaction, alkynylation of aryl halides in the absence of a copper cocatalyst and an external base. The dual nature of ChOH to act as a base and a green solvent played a crucial role in the catalytic cycle. The coupling reaction progressed efficiently to form a Csp-Csp2 bond under the identified conditions although the reaction outcome depended significantly on the substrates.
- Jung, Da-Young,Kim, Seung-Hoi,Park, Soo Youl
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supporting information
(2021/11/09)
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- An unsymmetrical Schiff-base derived recyclable Pd-catalyst for Suzuki–Miyaura and Sonogashira reactions in aqueous media
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Abstract: A water-soluble palladium (II) complex containing an unsymmetrical Schiff-base ligand was synthesized and applied as catalyst Suzuki–Miyaura and Sonogashira cross-coupling reactions in aqueous media. Notably, moderate to excellent yields of biaryls were obtained in Suzuki reaction with usually less reactive aryl and heteroaryl chlorides under relatively mild condition. Moderate-to-high yields of aryl-alkynes were also obtained in Sonogashira reactions using aryl bromides. Apart from hydrophilic nature, the accomplishment of reactions in water, high recyclability, broad functional group tolerance, etc., are other advantages of the system. Graphic abstract: [Figure not available: see fulltext.]
- Das, Pankaj,Gogoi, Achinta,Puzari, Amlan
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- Synthesis of a Cellulosic Pd(salen)-Type Catalytic Complex as a Green and Recyclable Catalyst for Cross-Coupling Reactions
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Abstract: A green recyclable cellulose-supported Pd(salen)-type catalyst was synthesized through sequential three steps: chlorination with thionyl chloride, modification by ethylenediamine, and the formation of Schiff base with salicylaldehyde to immobilize palladium chloride through multiple binding sites. This novel heterogeneous cellulosic Pd(salen)-type catalytic complex was fully characterized by FT-IR, SEM, TEM, XPS, ICP-AES and TG. The traditional cross-coupling chemistry, such as Suzuki, Heck, Sonogashira, Buchwald–Hartwig amination and etherification, was then investigated in the presence of the above cellulose-palladium nanoparticle. Studies have shown that the synthesized catalyst shows high activity and efficiency for all types of transformations, providing the corresponding carbon–carbon or carbon–heteroatom coupling products in a general and mild manner. Furthermore, the catalyst demonstrates high to excellent yields and is easily recycled by simple filtration for up to twelve cycles without any significant loss of catalytic activity. Graphic Abstract: [Figure not available: see fulltext.]
- Sun, Peng,Yang, Jiaojiao,Chen, Chunxia,Xie, Kaijun,Peng, Jinsong
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p. 2900 - 2910
(2020/03/31)
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- A conjugated microporous polymer as a recyclable heterogeneous ligand for highly efficient regioselective hydrosilylation of allenes
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Pyridines containing adjacent CC bonds were utilized as ligand units and integrated into the skeleton of conjugated microporous polymers. The resultant Pd-CMP-1 was first applied as a highly efficient heterogeneous catalytic system for Pd-catalyzed allene hydrosilylation towards a wide range of allenes to produce branched allylsilanes with high regioselectivity. The ligand units of the polymer, along with the confinement effect of the porous structure, jointly regulated the regioselectivity. The parts-per-million (ppm) levels of Pd, coordinated with the recyclable heterogeneous ligand, show promise for industrial applications. This work opens a new front of using CMP as an intriguing platform for developing highly efficient catalysts to control the regioselectivities in allene hydrosilylation.
- Jiang, Ya-Nan,Zeng, Jia-Hao,Yang, Ying,Liu, Zhi-Kai,Chen, Jun-Jia,Li, Ding-Chang,Chen, Li,Zhan, Zhuang-Ping
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supporting information
p. 1597 - 1600
(2020/02/13)
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- Nickel-Catalyzed Allylmethylation of Alkynes with Allylic Alcohols and AlMe3: Facile Access to Skipped Dienes and Trienes
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We present herein an unprecedented allylative dicarbofunctionalization of alkynes with allylic alcohols. This simple catalytic procedure utilizes commercially available Ni(COD)2, triphenylphosphine, and inexpensive reagents, and delivers valuable skipped dienes and trienes with an all-carbon tetrasubstituted alkene unit in a highly stereoselective fashion. Preliminary mechanistic studies support the reaction pathway of allylnickelation followed by transmetalation in this dicarbofunctionalization of alkynes.
- Li, Jincan,Li, Wanfang,Yu, Shun,Zhao, Yu
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supporting information
p. 14404 - 14408
(2020/07/04)
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- Facile Access to Diverse Libraries of Internal Alkynes via Sequential Iododediazoniation/Decarboxylative Sonogashira Reaction in Imidazolium ILs without Ligand or Additive
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Convenient access to diverse libraries of internal alkynes via decarboxylative Sonogashira reaction of alkynyl-carboxylic acids with iodoarenes, employing imidazolium-ILs as solvent, along with piperidine-appended imidazolium [PAIM][NTf2] as task-specific basic IL is demonstrated, without the need for any ligand or additive. The feasibility to perform these reactions by sequential one-pot iododediazoniation/decarboxylative Sonogashira reaction is also shown, and the scope of the methods is underscored by providing 29 examples. The potential for recycling and reuse of the IL solvent is also examined.
- Prabhala, Pavankumar,Savanur, Hemantkumar M.,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
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p. 2061 - 2064
(2019/03/07)
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- Stereo- and regioselective gold(i)-catalyzed hydroamination of 2-(arylethynyl)pyridines with anilines
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The gold-catalyzed hydroamination of 2-(arylethynyl)pyridines with anilines affords stereoselectively Z-enamine products with excellent regioselectivity. The reaction proceeds with moderate to excellent yields and accommodates a diverse range of functional groups on alkynes (ether, bromo, trifluoromethyl, acetyl, and carbomethoxy) and anilines (ether, bromo, chloro, and carbethoxy). The stereochemistry of the obtained enamines is complementary to that reported in previous studies. A plausible explanation for the observed selectivity was attained by means of NMR experiments.
- Cacchi, Sandro,Fabrizi, Giancarlo,Fochetti, Andrea,Ghirga, Francesca,Goggiamani, Antonella,Iazzetti, Antonia
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supporting information
p. 527 - 532
(2019/01/24)
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- Benzimidazolyl Palladium Complexes as Highly Active and General Bifunctional Catalysts in Sustainable Cross-Coupling Reactions
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A family of air- A nd moisture-stable dinuclear palladium complexes bearing 2-benzimidazolyl ligands is reported and shown to be a highly effective and general catalytic platform in diverse cross-coupling reactions. The rigidity and conformation of the ligand scaffold was readily modified via tethering of the 2-benzimidazolyl moiety to diamine ligands, resulting in significant changes in catalytic activity. Under optimal conditions, Suzuki, Heck, and Sonogashira-type couplings of aryl bromides can all be performed efficiently with good functional group compatibility using only 0.1 mola?% of catalyst, in aqueous or alcohol solvents. Experimental evidence highlights the importance of the bifunctional character of the ligand for catalytic activity, where the basic N-functionality in the ligand framework is proposed to accelerate (trans)metalation steps via intramolecular assistance.
- Zhu, Jiancheng,Lindsay, Vincent N. G.
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p. 6993 - 6998
(2019/08/26)
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- Gold-Catalyzed Oxidation of Internal Alkynes into Benzils and its Application for One-Pot Synthesis of Five-, Six-, and Seven-Membered Azaheterocycles
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Internal alkynes have been shown to undergo oxidation to substituted benzils (1,2-diarylethane-1,2-diones) by α-picoline N-oxide in the presence of Ph3PAuNТf2 (5 mol-%). In addition to the unsubstituted benzil, the method allows preparing, under markedly mild conditions (50 °C in chlorobenzene), various non-symmetrical products, including heteroaromatic versions thereof which are much more difficult to obtain otherwise. This gold(I)-catalyzed transformation was integrated into one-pot reaction sequence delivering a range of 5- to 7-membered ring systems (imidazoles, quinoxalines, 1,2,4-triazines, pyrazines, and 1,4-diazepines), thus linking these important heterocyclic motifs to the internal alkyne reagent space.
- Dubovtsev, Alexey Yu.,Dar'in, Dmitry V.,Krasavin, Mikhail,Kukushkin, Vadim Yu.
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supporting information
p. 1856 - 1864
(2019/02/19)
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- Visible-light induced copper(i)-catalysed denitrogenative oxidative coupling of hydrazinylpyridines with terminal alkynes
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Visible light mediated copper catalysed denitrogenative oxidative coupling of 2-hydrazinopyridines with terminal alkynes to form 2-(alkyl/arylethynyl) pyridines in the presence of O2 at room temperature is reported with 42 examples. This is the first report on visible light stimulated N2 elimination by an in situ generated copper(ii) superoxo/peroxo complex. N2 and water are the only by-products. The green chemistry metrics evaluation signifies that the current method is ecofriendly and economically feasible. This method allows the green synthesis of mGluR5 receptor antagonists, 2-methyl-6-(phenylethynyl)pyridine (MPEP) and 2-((3-methoxyphenyl)ethynyl)-6-methylpyridine (M-MPEP).
- Charpe, Vaibhav Pramod,Hande, Aniket A.,Sagadevan, Arunachalam,Hwang, Kuo Chu
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p. 4859 - 4864
(2018/11/21)
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- Development of highly electron-deficient and less sterically-hindered phosphine ligands possessing 1,3,5-triazinyl groups
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Highly electron-deficient and less sterically-hindered phosphine ligands with two or three 1,3,5-triazinyl groups on the phosphorus atoms have been synthesized and examined in transition metal-catalyzed reactions for the first time. Due to the lack of any hydrogens or substituents at ortho-positions of the 1,3,5-triazine towards the phosphorous atom, it is considered that the steric hindrance of the tris(triazinyl)phosphine ligand to a metal center is least among triarylphosphine ligands. In the Stille coupling of aryl iodides, these electron-poor phosphine ligands provided good product yields compared to hitherto well-known phosphine ligands.
- Abe, Kazumi,Kitamura, Masanori,Fujita, Hikaru,Kunishima, Munetaka
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- Sonogashira-type cross-coupling reactions catalyzed by copper complexes of pincer N-heterocyclic carbenes
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Copper complexes of N-heterocyclic carbenes (NHC) have recently received great attention in catalysis, however, the application scope has been limited to neutral complexes bearing monodentate ligands. Herein, we report the synthesis and full characterization of a cationic Cu-pincer bis(NHC) complex with bulky tert-butyl wingtips that serves as catalyst for the coupling of aryl iodides and phenylacetylene, alongside its analogs with small alkyl substituents. Unlike other copper catalysts that require an inert atmosphere to prevent alkyne homocoupling, a competing side reaction to Sonogashira reaction, the Cu-pincer bis(NHC) complexes provide good to excellent cross-coupling yields in air. Interestingly, the reaction under argon affords substantially reduced cross-coupling, indicative of the oxygen involvement and its facilitating effect in the mechanism. In our controlled studies, the air-assisted cross-coupling reaction came to a complete stop when using a radical trap, suggesting the presence of a radical in the mechanism. Examining the reaction of Cu-pincer bis(NHC) complexes with oxygen via UV–vis spectroscopy reveals a dark green chromophore formation at ?40 °C with strong absorbance (ε > 400 M?1cm?1) at 460 nm and 500 nm, likely due to a high-valent copper-oxygen adduct.
- Domyati, Doaa,Latifi, Reza,Tahsini, Laleh
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supporting information
p. 98 - 105
(2018/03/06)
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- Method for synthesizing phenylethynyl pyridine derivative
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The invention discloses a method for synthesizing a phenylethynyl pyridine derivative. The method takes palladium acetate as a catalyst, 4,5-bisdiphenylphosphine-9,9-dimethoxyxanthene as a ligand andmethanol as a solvent; 2-iodopyridine and a phenylacetylene type compound are coupled to prepare the phenylethynyl pyridine derivative. The method disclosed by the invention has the advantages of simplicity in operation, efficient reaction, moderate conditions and good substrate applicability and can be widely used for preparing the phenylethynyl pyridine derivative.
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Paragraph 0014; 0015; 0016; 0017
(2018/12/02)
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- Heterogenized Cu (II) salen complex grafted on graphene oxide nanosheets as a precursing catalyst for the Pd-free Sonogashira coupling
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Cu (II) salen complex immobilized on graphene oxide nanosheets [Cu (II) salen@GO] was synthesized with 3-chloropropyltrimethoxysilan as a linker and wholly characterized using various techniques like X-ray diffraction, Fourier-transform infrared, scanning electron microscopy/energy-dispersive X-ray spectroscopy, transmission electron microscopy, as well as atomic absorption spectroscopy (AAS). Cu (II) salen@GO as an effective heterogeneous catalyst has been investigated for the Sonogashira coupling reaction in dimethylsulfoxide with good to high yield (98%) in 4?hr at 110°C when the loading of Cu was 0.7?mmol?g?1 based on Cu element analysis by AAS. It was understood that heterogeneous catalyst was as active as its homogeneous analog, and presented good recoverability and no significant loss in activity within successive runs.
- Ghabdian, Mahdieh,Nasseri, Mohammad A.,Allahresani, Ali,Motavallizadehkakhky, Alireza
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- Novel oxime-palladacycle supported on clay composite as an efficient heterogeneous catalyst for Sonogashira reaction
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A novel supported catalyst formed by an oxime-derived palladacycle supported on clay OxPdCy@clay is synthesized and characterized. This palladium composite promotes the Sonogashira reaction of aryl iodides, bromides and chlorides with terminal alkynes in polyethylene glycol200 at 85 or 130 °C using 0.05–0.1 mol% of palladium loading under copper and phosphine free conditions. This supported palladacycle, OxPdCy@clay, showed a superior catalytic activity than dimeric oxime-palladacycles. Mechanistic studies about the heterogeneous or homogeneous nature of the catalyst show that catalyst is working mainly under heterogeneous conditions. This supported palladacycle OxPdCy@clay can be recycled by simple centrifugation and reused for at least nine consecutive runs with small decrease in activity.
- Gholinejad, Mohammad,Dasvarz, Neda,Nájera, Carmen
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p. 262 - 270
(2018/09/06)
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- Synthesis, crystal structures, and application of two new pincer type palladium(II)-Schiff base complexes in C-C cross-coupling reactions
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Two new pincer type Pd(II)-Schiff base complexes of the general formula [PdL1(PPh3)] 1 and [PdL2(PPh3)] 2, (where L1 = 2-(2,3-Dihydroxybenzylideneamino)phenolate and L2 = 2-(2,3-dihydroxybenzylidene)hydrazinecarbothioamidate) were synthesised by the reaction of the palladium acetate with the corresponding ligand in methanol as yellow crystalline solids in high yields. Both complexes were fully characterized by FT-IR, 1H NMR, 13C NMR, 31P NMR, elemental analysis and single crystal X-ray diffraction studies. The crystal structures confirmed the tridentate nature of the pincer type Schiff base ligands and the distorted square planar geometry around the metal centre in both cases. The triphenylphosphine acted as an auxiliary ligand and occupied the fourth coordination site at palladium. The complexes were found to be efficient homogenous catalysts for a series of Suzuki-Miyaura, Heck-Mizoroki and Sonogashira reactions at a low catalyst loading (0.08 mol%), and without the use of any additives. All organic products were fully characterized by 1H and 13C NMR studies.
- Agrahari, Bhumika,Layek, Samaresh,Anuradha,Ganguly, Rakesh,Pathak, Devendra D.
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p. 345 - 354
(2017/12/01)
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- Direct preparation of arylethynylzinc bromides and their application to cross-coupling reactions
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A novel synthetic protocol for the preparation of arylethynylzinc bromides has been developed. Thus-obtained organozinc reagents were successfully employed in the subsequent cross-coupling reactions with a broad range of aryl halides providing the corresponding alkynylated compounds in good to excellent yields.
- Joo, Seong-Ryu,Kim, Jong-Sung,Kim, Seung-Hoi
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p. 3267 - 3270
(2017/07/27)
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- Transformation of Carbonyl Compounds into Homologous Alkynes under Neutral Conditions: Fragmentation of Tetrazoles Derived from Cyanophosphates
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Cyanophosphates (CPs) can be easily prepared from either ketones or aldehydes, and their reaction with NaN3-Et3N·HCl results in the formation of azidotetrazoles. Under microwave irradiation, successive fragmentation of the azidotetrazoles generates alkylidene carbenes that undergo [1,2]-rearrangement and are transformed into homologous alkynes. Treatment of ketone-derived CPs with TMSN3 and Bu2SnO as catalyst in toluene at reflux directly yields the corresponding internal alkynes, whereas the reaction of aldehyde-derived CPs with NaN3-Et3N·HCl in THF at reflux or TMSN3-Bu2SnO (cat.) in toluene at reflux provides homologous terminal alkynes in good yields. These reactions take place under neutral conditions and can be successfully extended to obtain alkynes that are not usually accessible from the corresponding carbonyl compounds by the Ohira-Bestmann or Shioiri procedures, which require basic conditions.
- Yoneyama, Hiroki,Numata, Masahiro,Uemura, Kenji,Usami, Yoshihide,Harusawa, Shinya
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p. 5538 - 5556
(2017/06/07)
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- Ligand- and copper-free Sonogashira and Heck couplings of (Het)aryl chlorides and bromides catalyzed by palladium nanoparticles supported on in situ generated Al(OH)3
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The ligand- and copper-free Sonogashira reaction of (Het)aryl halides (Br and Cl) with various terminal alkynes and the Heck coupling of (Het)aryl halides (Br and Cl) with a series of olefins, catalyzed by palladium nanoparticles supported on newly generated Al(OH)3, were developed. The catalyst can be readily recovered and reused 6 times without significant loss of activity and palladium leaching.
- Li, Xing,Gong, Xiaolei,Li, Zhipeng,Chang, Honghong,Gao, Wenchao,Wei, Wenlong
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p. 2475 - 2479
(2017/02/05)
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- Phosphinito palladium(ii) complexes as catalysts for the synthesis of 1,3-enynes, aromatic alkynes and ynones
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An air-stable phosphinito palladium(ii) complex (Ph1-Phoxide) has been found to be an efficient catalyst in the formation of C-C bonds. The coupling of terminal alkynes formed gem-1,3-enynes as the only reaction products. Aromatic alkynes can be synthesized from the coupling of terminal alkynes and haloaromatic compounds (Sonogashira coupling). The phosphinito palladium(ii) complex also catalyses the coupling between acyl chlorides and terminal alkynes (Sonogashira coupling), furnishing ynones in excellent yields.
- Islas,Cárdenas,Gavi?o,García-Ríos,Lomas-Romero,Morales-Serna
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p. 9780 - 9789
(2017/02/15)
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- Deep Eutectic Solvent Compatible Metallic Catalysts: Cationic Pyridiniophosphine Ligands in Palladium Catalyzed Cross-Coupling Reactions
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Cationic pyridiniophosphine ligands have been synthetized in an attempt to develop a deep eutectic solvents (DESs) compatible catalytic systems. These ligands, in combination with PdCl2, have been successfully applied to different palladium-catalyzed cross coupling reactions, such as Suzuki–Miyaura, Sonogashira, or Heck couplings. While traditional palladium ligands in DES medium failed to reproduce the results obtained in VOC solvents, these cationic phosphines improved the catalytic activity of palladium as no other traditional ligand could in such a polar medium. In addition, the recyclability of these processes was studied, allowing us to reuse both, catalyst and solvent up to 5 times in Suzuki and Sonogashira reactions without a significant drop in the catalytic activity. Regarding the structure of the Pd catalysts, titration, NMR, and DFT studies have clearly demonstrated the coordination properties of the DES-compatible cationic phosphine ligands.
- Marset, Xavier,Khoshnood, Abbas,Sotorríos, Lia,Gómez-Bengoa, Enrique,Alonso, Diego A.,Ramón, Diego J.
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p. 1269 - 1275
(2017/04/14)
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- Conjugated Microporous Polymer as Heterogeneous Ligand for Highly Selective Oxidative Heck Reaction
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A series of pyridine-type ligands containing C C bonds were designed and synthesized for selective oxidative Heck reaction. These ligands were utilized as functional units and integrated into the skeleton of conjugated microporous polymers. 6,6′-diiodo-2,2′-bipyridine and 1,3,5-triethynylbenzene were polycondensed via Sonogashira cross-coupling strategy to afford CMP-1 material. The resultant CMP-1 was used as a heterogeneous catalytic ligand for the PdII-catalyzed oxidative Heck reaction with high linear selectivity. The linear selectivity of CMP-1 is about 30 times higher than that of bipyridine-based monomer ligand. This work opens a new front of using CMP as an intriguing platform for developing highly efficient catalysts in controlling the regioselectivity in organic reactions.
- Zhou, Yun-Bing,Wang, Yu-Qing,Ning, Li-Chao,Ding, Zong-Cang,Wang, Wen-Long,Ding, Cheng-Ke,Li, Ren-Hao,Chen, Jun-Jia,Lu, Xin,Ding, Yun-Jie,Zhan, Zhuang-Ping
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supporting information
p. 3966 - 3969
(2017/03/27)
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- Three-Component One-Pot Synthesis of Unsymmetrical Diarylalkynes by Thermocontrolled Sequential Sonogashira Reactions Using Potassium Ethynyltrifluoroborate
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Unsymmetrical diarylalkynes were synthesized in moderate to good yields through a three-component one-pot procedure involving thermocontrolled sequential Sonogashira reactions with potassium ethynyltrifluoroborate and two different reactive aryl halides. The one-pot procedure was initiated by the palladium/copper-catalyzed Sonogashira coupling of potassium ethynyltrifluoroborate to an aryl iodide or electron-deficient aryl bromide at 40 °C. Following a subsequent deboronative Sonogashira reaction of the in situ generated potassium (arylethynyl)trifluoroborate, a second coupling to a less-active electron-rich aryl bromide at 80 °C, without any additional palladium/copper catalyst or base, gave rise to unsymmetrical diarylalkynes.
- Kim, Taejung,Jeong, Kyu Hyuk,Kim, Youngseok,Noh, Taesub,Choi, Jaeyoung,Ham, Jungyeob
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p. 2425 - 2431
(2017/05/12)
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- Tetraalkynylstannanes in the Stille cross coupling reaction: a new effective approach to arylalkynes
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The Stille-type cross coupling reaction with tetraalkynylstannanes was studied in detail for the first time. The reaction provides a simple and effective route towards a variety of arylalkynes. The advantages and limitations of the proposed procedure are discussed.
- Levashov, Andrey S.,Buryi, Dmitrii S.,Goncharova, Olga V.,Konshin, Valeriy V.,Dotsenko, Victor V.,Andreev, Alexey A.
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supporting information
p. 2910 - 2918
(2017/04/14)
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- Supported palladium nanoparticles-catalyzed decarboxylative coupling approaches to aryl alkynes, indoles and pyrrolines synthesis
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The polystyrene supported palladium (Pd@PS) nanoparticles (NPs) catalyzed decarboxylative coupling (DC) of arylhalides and alkynyl carboxylic acids was developed for the synthesis of diaryl alkynes. Indole and 3-pyrroline heterocycles were also synthesized from 2-iodo anilines/amino benzocycloheptene bromide and alkynyl carboxylic acids, following a domino decarboxylative coupling-cyclization (DCC) approach under the same catalytic conditions. The combined anchoring and catalytic behaviour of Pd@PS makes the process favourable for the product formation.
- Reddy, C. Bal,Bharti, Richa,Kumar, Sandeep,Das, Pralay
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p. 71117 - 71121
(2016/08/05)
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- Scope and limitations of a DMF bio-alternative within Sonogashira cross-coupling and Cacchi-type annulation
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Pd-catalysed C-C bond formation is an essential tool within the pharmaceutical and agrochemical industries. Many of these reactions rely heavily on polar aprotic solvents; however, despite their utility, these solvents are incompatible with the drive towards more sustainable chemical synthesis. Herein, we describe the scope and limitations of an alternative to DMF derived from renewable sources (Cyrene) in Sonogashira cross-coupling and Cacchi-type annulations.
- Wilson, Kirsty L.,Kennedy, Alan R.,Murray, Jane,Greatrex, Ben,Jamieson, Craig,Watson, Allan J. B.
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supporting information
p. 2005 - 2011
(2016/10/05)
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- Gram-Scale Preparation of Pd@PANI: A Practical Catalyst Reagent for Copper-Free and Ligand-Free Sonogashira Couplings
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Palladium nanoparticles on the polyaniline (Pd@PANI) catalyst are now easily prepared on a gram scale through the oxidative polymerization of aniline in the presence of PdCl2 by using air as a clean oxidant. The material is found to be very stable and can be stored for more than one year without deactivation. Thus, it may become a commercial reagent in organic synthesis, depending on its application scopes. This article reported the first example of Pd@PANI-catalyzed Sonogashira couplings free of copper and ligands.
- Yu, Lei,Han, Zhe,Ding, Yuanhua
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p. 2124 - 2129
(2016/12/24)
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- Manganese-catalyzed Sonogashira coupling of aryl iodides
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An interesting manganese-catalyzed Sonogashira coupling reaction of aryl iodides has been developed. With PEG-400 as the green solvent and under mild reaction conditions, a variety of diarylacetylenes were obtained in moderate to good yields.
- Qi, Xinxin,Jiang, Li-Bing,Wu, Xiao-Feng
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supporting information
p. 1706 - 1710
(2016/04/04)
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- Sonogashira coupling catalyzed by the Cu(Xantphos)I–Pd(OAc)2system
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An efficient Pd(OAc)2/Cu(Xantphos)I system for Sonogashira coupling is disclosed. Aryl bromides/iodides and electron-poor aryl chlorides were suitable for this reaction. The experimental results suggest that Cu(Xantphos)I plays a unique role in which the phosphine ligand coordinates with copper.
- Liu, Meilin,Ye, Mingyan,Xue, Yeye,Yin, Guodong,Wang, Dunjia,Huang, Jinkun
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supporting information
p. 3137 - 3139
(2016/07/06)
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- Palladium supported on bis(indolyl)methane functionalized magnetite nanoparticles as an efficient catalyst for copper-free Sonogashira-Hagihara reaction
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A novel heterogeneous catalyst based on palladium nanoparticles supported on 3,3′-bisindolyl(4-hydroxyphenyl)methane functionalized magnetite (Fe3O4) nanoparticles was synthesized, characterized and used as catalyst for Sonogashira-Hagihara reaction. The alkynylation of a variety of aryl iodides and aryl bromides with terminal alkynes was carried out at 60?°C under copper and phosphane-free conditions using N,N-dimethyl acetamide as solvent, DABCO as base and low Pd loadings (0.18 mol%) under air. In the case of aryl chlorides, the reaction was carried out at 120?°C in the presence of tetra-n-butylammonium bromide (TBAB) and 0.36 mol% of Pd catalyst. The heterogeneous palladium catalyst introduced in this study is recoverable by an external magnet and it can be used for seven consecutive runs without a significant loss in catalytic activity.
- Gholinejad, Mohammad,Neshat, Abdollah,Zareh, Fatemeh,Nájera, Carmen,Razeghi, Mehran,Khoshnood, Abbas
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- Organocatalytic synthesis of alkynes
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Carbon-carbon triple bonds of alkynes are ubiquitous. They serve as valuable starting materials that can be transformed into a vast array of diverse materials, with applications ranging from medicinal chemistry to electronic materials. The methods used to prepare alkynes involve stoichiometric reactions and the most popular install only a single carbon rather than uniting larger fragments. These methods are useful, but they are limited by harsh conditions or the need to prepare reagents. Introduced herein is the first catalytic method to prepare carbon-carbon triple bonds from precursors that do not contain such linkages. By coupling benzaldehyde and benzyl chloride derivatives under basic conditions with an organocatalyst, good yields of alkynes are obtained. The catalyst, a highly reactive sulfenate anion, is readily generated under the reaction conditions from air-stable precursors. This method represents an attractive organocatalytic alternative to well-established stoichiometric approaches to alkynes and to transition-metal-based alkyne functionalization methods in various applications.
- Zhang, Mengnan,Jia, Tiezheng,Wang, Carol Y.,Walsh, Patrick J.
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supporting information
p. 10346 - 10350
(2015/09/01)
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- Stabilized naked Sub-nanometric Cu clusters within a polymeric film catalyze C-N, C-C, C-O, C-S, and C-P bond-forming reactions
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Sub-nanometric Cu clusters formed by endogenous reduction of Cu salts and Cu nanoparticles are active and selective catalysts for C-N, C-C, C-O, C-S, and C-P bond-forming reactions. Sub-nanometric Cu clusters have also been generated within a polymeric film and stored with full stability for months. In this way, they are ready to be used on demand and maintain high activity (TONs up to 104) and selectivity for the above reactions. A potential mechanism for the formation of the sub-nanometric clusters and their electronic nature is presented.
- Oliver-Messeguer, Judit,Liu, Lichen,García-García, Saray,Canós-Giménez, Claudia,Domínguez, Irene,Gavara, Rafael,Doménech-Carbó, Antonio,Concepción, Patricia,Leyva-Pérez, Antonio,Corma, Avelino
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supporting information
p. 3894 - 3900
(2015/04/14)
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- Efficient Sonogashira and Suzuki-Miyaura coupling reaction catalyzed by Pd-Nanoparticles
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The Pd nano particles were electrochemically deposited on nafion-graphene. They showed excellent catalytic activity towards Sonogashira and Suzuki-Miyaura cross-coupling reaction. Benzenediazonium salts were used as alternative to aromatic halide. The developed protocol offers recyclability, easy workups with short reaction time and good-to-excellent product yield. [Figure not available: see fulltext.]
- Balsane, Kishor E.,Shendage, Suresh S.,Nagarkar, Jayashree M.
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p. 425 - 431
(2015/05/13)
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- 3,6-Di(pyridin-2-yl)-1,2,4,5-tetrazine capped Pd(0) nanoparticles: A catalyst for copper-free Sonogashira coupling of aryl halides in aqueous medium
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3,6-Di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) capped Pd(0) nanoparticles (TzPdNPs) as a catalyst in the Sonogashira coupling of aryl halides in aqueous medium with diminished homocoupling is reported. The methodology provides a facile route to obtain polyfunctional alkynes under ligand- and copper-free conditions. The procedure is also efficient for aryl chlorides.
- Das, Sudipto,Samanta, Suvendu,Ray, Shounak,Biswas, Papu
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p. 75263 - 75267
(2015/09/21)
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- Synthesis of 4-sulfonatobenzylphosphines and their application in aqueous-phase palladium-catalyzed cross-coupling
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Aqueous-biphasic catalysis offers the potential for safer and more environmentally sustainable synthetic processes. In addition, hydrophilic supporting ligands allow homogeneous catalysts to be readily separated from organic products and potentially reused. The synthesis of two new water-soluble ligand precursors, di-tert-butyl(4-sulfonatobenzyl)phosphonium and di-1-adamantyl(4-sulfonatobenzyl)phosphonium, are reported. The air-stable, zwitterionic phosphonium salts were prepared by the reaction of dialkylphosphines with ethyl 4-bromomethylbenzenesulfonate, which results in a one-pot alkylation followed by deprotection of the ethyl sulfonate. This methodology provides an operationally simpler route to sulfonated benzylphosphines than electrophilic sulfonation. The new phosphine ligands were applied to aqueous-phase Suzuki and Sonogashira couplings of aryl bromides.
- Moore, Jane N.,Laskay, Nicholas M.,Duque, Kevin S.,Kelley, Steven P.,Rogers, Robin D.,Shaughnessy, Kevin H.
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supporting information
p. 16 - 24
(2015/02/05)
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