- Conformationally controlled electron delocalization in n-type rods: Synthesis, structure, and optical, electrochemical, and spectroelectrochemical properties of dicyanocyclophanes
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A series of dicyanobiphenylcyclophanes 1-6 with various π-backbone conformations and characteristic n-type semiconductor properties is presented. Their synthesis, optical, structural, electrochemical, spectroelectrochemical, and packing properties are investigated. The X-ray crystal structures of all n-type rods allow the systematic correlation of structural features with physical properties. In addition, the results are supported by quantum mechanical calculations based on density functional theory. A two-step reduction process is observed for all n-type rods, in which the first step is reversible. The potential gap between the reduction processes depends linearly on the cos2 value of the torsion angle ψ between the π-systems. Similarly, optical absorption spectroscopy shows that the vertical excitation energy of the conjugation band correlates with the cos2 value of the torsion angle ψ. These correlations demonstrate that the fixed intramolecular torsion angle ψ is the dominant factor determining the extent of electron delocalization in these model compounds, and that the angle ψ measured in the solid-state structure is a good proxy for the molecular conformation in solution. Spectroelectrochemical investigations demonstrate that conformational rigidity is maintained even in the radical anion form. In particular, the absorption bands corresponding to the SOMO-LUMO+i transitions are shifted bathochromically, whereas the absorption bands corresponding to the HOMO-SOMO transition are shifted hypsochromically with increasing torsion angle ψ. Copyright
- Vonlanthen, David,Rudnev, Alexander,Mishchenko, Artem,Kaeslin, Alexander,Rotzler, Juergen,Neuburger, Markus,Wandlowski, Thomas,Mayor, Marcel
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- Viologen as catalytic organic reductant: Electro-reductive dimerization of aryl bromides in a Pd/viologen double mediatory system
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Viologen can be used as an in situ recyclable organic reductant. Pd-catalyzed electrochemical reductive coupling of aryl bromides was performed by using a catalytic amount of viologen to afford the corresponding biaryls in good to moderate yields.
- Kuroboshi, Manabu,Shiba, Takuya,Tanaka, Hideo
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- Synthesis of 2-X-, 3-X-4,4′-Dicyanobiphenyls (X = CH3, OCH3, F) by Cross-Coupling of the Terephthalonitrile Dianion with Substituted Benzonitriles
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A concise noncatalytic synthetic approach to 2- and 3-substituted 4,4′-dicyanobiphenyls by applying terephthalonitrile dianion 12- as para-cyanophenylating reagent for neutral benzonitriles is described. Neutral participants are varied to reveal the scope of applicable substrates and to evaluate the electronic and structural factors governing the regioselectivity and efficiency of the cross-coupling. Benzonitriles substituted with Me, OMe and F provide the corresponding dicyanobiphenyls in good yields. The regularities in the reactivities are interpreted in terms of a reaction scheme involving the intermediacy of a charge-transfer complex between 12- and benzonitrile, which transforms into a dimeric dianion either through a heterolytic pathway and/or by successive single electron transfer and recombination of the primary generated radical anions. Quantum chemical calculations of the structure and energy of the principal reaction intermediates match the experimental data. CV measurements of the new dicyanobiphenyls are also included. Transition-metal-free biaryl cross-coupling utilises the terephthalonitrile dianion sodium salt for para-cyanophenylation of aromatic nitriles modified with methoxy, methyl, and fluorine substituents, with the formation of 2- and 3-substituted 4,4′-dicyanobiphenyls. The proposed reaction scheme is verified by quantum chemical calculations.
- Peshkov, Roman Yu.,Panteleeva, Elena V.,Shchegoleva, Lyudmila N.,Bagryanskaya, Irina Yu.,Rybalova, Tatyana V.,Vasilieva, Nadezhda V.,Shteingarts, Vitalij D.
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- The homocoupling of arylsulfonylhydrazides by palladium-catalysed desulfonation in air
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A simple and efficient preparation of biaryl derivatives from arylsulfonyl hydrazides has been developed using Pd(OAc)2 as the catalyst in a mixed solvent of DMA and THF and without the use of any ligand and base.
- Zhang, Wei,Zhao, Baoli,Li, Ke
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- Oxidative homocoupling of arylboronic acids catalyzed by a 4-aminoantipyrine-Pd(II)complex
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A one-step synthesis of symmetric biaryls is reported under very mild conditions via the homocoupling reaction of substituted arylboronic acids using an air- and moisture-stable 4-aminoantipyrine-Pd(II) complex as catalyst. The reaction is conducted at a low catalyst loading of 0.1 mol% at room temperature in methanol in the presence of K2CO3 as the base and KMnO4 as the oxidant. The catalytic methodology is shown to be compatible with diverse functional groups and affords the desired biphenyls in good to excellent yields.
- Contreras-Celedón, Claudia Araceli,Rincón-Medina, José Arturo,Mendoza-Rayo, Darío,Chacón-García, Luis
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- Rapid gram-scale synthesis of Au/chitosan nanoparticles catalysts using solid mortar grinding
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Owing to the abundant functional groups present in the chitosan polymer, high density catalytic tiny gold particles with greater dispersion can be anchored on the chitosan powder using simple mortar and pestle. Chitosan-supported gold nanoparticles (NPs) with excellent control of size and shape were rapidly synthesized in gram-scale by solid-grinding without the need of any toxic solvents. The structure of catalysts and products was established by advanced instrumental and spectroscopic methods. The supported gold NPs functions as a heterogeneous catalyst for the homocoupling of phenylboronic acid and the aerobic oxidation of benzyl alcohol in water. The catalytic behaviour and activity of supported gold NPs was tuned/modulated by varying the ratio of chitosan polymer and gold precursor. Comparative studies showed that the solid chitosan supported gold catalyst exhibits superior catalytic activity and selectivity than the well known hydrophilic polymer-stabilized gold NPs catalysts prepared by the conventional solution-based methods.
- Reddy, K. Paul,Meerakrishna,Shanmugam,Satpati, Biswarup,Murugadoss
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- Catalytic properties of Au and Pd nanoparticles decorated on Cu 2O microcubes for aerobic benzyl alcohol oxidation and Suzuki-Miyaura coupling reactions in water
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The catalytic activities of Cu2O microcubes decorated with Au and Pd nanoparticles (Cu2O/Au and Cu2O/Pd) were synthesized by a microwave assisted technique and examined for the specific organic reactions, separately. Cu2O/Au and Cu2O/Pd catalysts were characterized and examined as the catalysts for the aerobic oxidation of benzyl alcohol to benzaldehyde and the Suzuki-Miyaura coupling reaction in water, separately. The yields of products were >90% with a selectivity of >99% for both catalytic reactions. The cheap, ligand free, efficient, non-toxic, and water soluble properties make the present catalyst ultimate for Suzuki and aerobic oxidation reaction.
- Prasad, K. Sudhakara,Noh, Hui-Bog,Reddy, S. Subba,Reddy, A. Eswar,Shim, Yoon-Bo
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- Nickel catalyzed one pot synthesis of biaryls under air at room temperature
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A practical, room temperature catalytic system has been developed for the synthesis of biaryls in one step from the homocoupling of in situ generated Grignard reagents using a nickel(ii) complex. The use of atmospheric oxygen as the oxidant makes the system environmentally friendly. The reaction system is compatible with diverse functionality to afford biaryls in appreciable yields. The Royal Society of Chemistry 2013.
- Bhat, Aparna P. I.,Inam, Fawad,Bhat, Badekai Ramachandra
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- Palladium nanoparticles immobilized on the magnetic few layer graphene support as a highly efficient catalyst for ligand free Suzuki cross coupling and homo coupling reactions
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In this study, we prepared a magnetic metal–graphene nanocomposite for the synthesis of substituted biaryls via Suzuki cross coupling and homo coupling reaction of aryl halides. The magnetic few layer graphene composite was synthesized by using one-step electrochemical exfoliation of graphite foil in aqueous iron (II) ammonium sulfate as electrolyte without using of any additive or corrosive media. Then, Fe2O3@FLG composite was used an efficient support for the immobilization and suitable dispersing of palladium nanoparticles. The obtained Fe2O3@FLG@Pd0 nanocomposite was characterized using FT-IR, SEM, TEM, EDS, XRD, VSM and ICP-AES analysis. Very low loading of this catalyst was displayed high activity in the producing substituted biaryls. It simply recovered from the reaction mixture and reused without any pre-activation in six consecutive runs with no loss of its catalytic activity or the observation of any detectable palladium leaching process.
- Rafiee, Fatemeh,Khavari, Parvaneh,Payami, Zahra,Ansari, Narges
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- Homocoupling of arylboronic acids catalyzed by simple gold salts
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A range of arylboronic acids undergo a homocoupling reaction in the presence of catalytic amount of gold salts to yield symmetrical biaryls. Alkenylboronic acids, arylboronic esters, and arylborates also participate in the gold-catalyzed homocoupling reaction.
- Matsuda, Takanori,Asai, Taro,Shiose, Shigeru,Kato, Kotaro
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- Ligand and Base Free Synthesis of Biaryls from Aryl Halides in Aqueous Media with Recyclable Ti0.97Pd0.03O1.97 Catalyst
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Abstract: Facile protocol for the synthesis of biaryls from aryl halides in presence of magnesium metal without prior formation of organometallic intermediate has been exploited. Irrespective of aqueous medium, Ti0.97Pd0.03O1.97 catalyst supports C–C bond formation reaction in presence of metals rather than dehalogenation without any additives. Homocoupling of 16 different aryl halides furnished corresponding biphenyls in good yield with better functional group tolerance. The recovery of the catalyst was carried out by employing catalyst coated cordierite monolith up to 7th cycle with high yields. A new approach for the cross-coupling reaction is also attempted. Graphic Abstract: [Figure not available: see fulltext.]
- Prasanna,Bhat, Shrikanth K.,Usha,Hegde
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- Efficient and durable Au alloyed Pd single-atom catalyst for the Ullmann reaction of aryl chlorides in water
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Ion exchange resin supported Au alloyed Pd single atoms have been explored to serve as an effective and robust catalyst for the Ullmann reaction of aryl halides under mild conditions in aqueous media, in particular for the activation of less reactive aryl chlorides. The catalysts were prepared with an ion exchange-NaBH4 reduction method and submitted to extensive characterizations by HRTEM, XRD, EXAFS, and DRIFTS techniques. XRD patterns demonstrated the formation of Au-Pd alloys. EXAFS and DRIFTS characterization results showed that with an increase of Au/Pd molar ratios, the continuous Pd ensembles on the surface were gradually separated and eventually isolated by Au atoms, confirming that the Au alloyed Pd single-atom catalyst was formed. The catalysts exhibited excellent performance for the Ullmann reaction of aryl chlorides, and the turnover number (TON) increased exponentially with a decrease of the amount of Pd in the catalysts. On the basis of these characterization and catalytic results, the Au alloyed Pd single-atom was proposed as the active site for the reaction. The catalyst exhibited excellent catalytic performance for a broad scope of substrates and could be reused at least 8 times with no change in yield. This Au alloyed Pd single-atom catalyst bridges the gap between homogeneous and heterogeneous catalysis in organic transformations and may open a new vision to develop other efficient single-atom catalysts for green synthesis of fine chemicals.
- Zhang, Leilei,Wang, Aiqin,Miller, Jeffrey T.,Liu, Xiaoyan,Yang, Xiaofeng,Wang, Wentao,Li, Lin,Huang, Yanqiang,Mou, Chung-Yuan,Zhang, Tao
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- Cobalt-catalyzed formation of symmetrical biaryls and its mechanism
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A method for cobalt-catalyzed formation of symmetrical biaryls and mechanism used for the formation, were reported. The study involved a new cobalt-catalyzed homo-coupling reaction in which cobalt was used with manganese dust as reducing agent. It was observed that the presence of allylchloride significantly reduced the amount of reduction compounds without modifying kinetics of the reactions and the reaction remained un-affected by the presence of air as oxidant. It was also found that no-reactions occurred in DMF, THF, and toluene in the presence of pyridine as co-solvent at room temperature, which indicated that MeCN acted as a ligand of the cobalt active species. The coupling process can be extended to less reactive aryl chlorides by changing some experimental conditions. DFT calculations revealed that the involvement of a CoI/CoIII couple was realistic in the case of 1,3-diazadienes as ligands.
- Moncomble, Aurelien,Floch, Pascal Le,Gosmini, Corinne
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- Ullmann homocoupling of aryl iodides catalyzed by gold nanoparticles stabilized on magnetic mesoporous silica
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Abstract: We demonstrated a convenient new procedure of the Ullmann homocoupling reaction for the synthesis of symmetrical biaryls via homocoupling of aryl iodides over a recyclable gold catalyst comprising Au nanoparticles supported on functional magnetic mesoporous silica (α-Fe2O3)-MCM-41-HS-Au. The catalyst was easily separated by an external magnet, and the recovered catalyst was reused in six successive reaction cycles without any significant loss of activity. So, using this catalyst is affordable. Also, the reaction time is much shorter than a few previously reported work. Graphical Abstract: [Figure not available: see fulltext.]
- Rostamizadeh, Shahnaz,Estiri, Hamid,Azad, Mohammad
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- Novel and efficient synthesis of symmetrical functionalized biaryls using zinc and triethylammonium formate
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Reductive homocoupling of aryl halides in the presence of commercial zinc dust and triethylammonium formate in methanol produces biaryls in good to excellent yields. Aryl halides having either electron-donating or electron-withdrawing groups underwent smooth coupling to afford the corresponding symmetrical biaryls. The reductive coupling did not occur without triethylammonium formate. Addition of one equivalent of sodium hydroxide enhanced the coupling reaction rate. The commercial zinc dust is inexpensive, widely available and can be used without any auxiliary catalysts such as Pd(0) and/or Ni(0).
- Abiraj,Srinivasa,Gowda, D. Channe
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- Facile synthesis of symmetrical functionalized biaryls from aryl halides catalyzed by commercial zinc dust using ammonium formate
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Reductive homocoupling of aryl halides in the presence of commercial zinc dust and ammonium formate in methanol produces biaryls in good to excellent yields. Aryl halides having either electron-donating or electron-withdrawing groups underwent smooth coupling to afford the corresponding symmetrical biaryls. Addition of 1equiv of sodium hydroxide enhanced the coupling reaction rate. Commercial zinc dust is inexpensive, widely available and can be used without any auxiliary catalysts such as Pd(0) and/or Ni(0).
- Abiraj,Srinivasa,Channe Gowda
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- Catalytic homocoupling of aryl, alkenyl, and alkynyl halides with Ni(II)-complexes and zirconocene dichloride
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A new catalytic system (cat. (H)2Phen(Me)2· NiCl2 or (MeO)2Dipyr(H)2·NiCl 2, cat. Zr(cp)2Cl2, 2 equiv Mn, and 2 equiv LiCl) has been developed to facilitate the homocoupling of a wide range of aryl, alkenyl, and alkynyl halides.
- Peng, Jianbiao,Liu, Xiang,Kishi, Yoshito
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- Pd-catalyzed homocoupling of arylhydrazines via C - N cleavage under O 2
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An efficient and simple synthetic method for biaryl synthesis was developed using Pd(OAc)2 as catalyst from aryl hydrazides under O2. Various biaryls were synthesized in good yields, offering an expedient protocol for the synthesis of symmetrical biaryl molecules via C - N cleavage. The reactions were performed in component solvent of toluene and acetone without using any pro-oxidant. Copyright
- Yao, Peng
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- Synthesis of functionalized diaryldimethylstannanes from the Me 2Sn2- dianion by SRN1 reactions
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The reaction of different ArCl with the Me2Sn2- dianion in liquid ammonia under irradiation afforded Ar2SnMe 2 in good yields (68-85%). The results obtained clearly indicate that the reaction proceeded through an SRN1 reaction. As a synthetic application of these Ar2SnMe2, the homocoupling is described in the presence of Cu(NO3)2·2.5H 2O to afford the biaryls. These reactions proceeded almost quantitatively.
- Uberman, Paula M.,Martin, Sandra E.,Rossi, Roberto A.
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- One-step synthesis of biaryls under mild conditions
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A one-step synthesis of symmetrical biaryls was developed and uses a nickel(III) complex containing a Schiff base and dithiolate ligands as a catalyst for the homocoupling of in situ generated Grignard reagents. The coupling reaction was performed at room temperature with molecular oxygen as the oxidant, which renders the reaction energy-efficient and environmentally friendly. The catalytic methodology is compatible with diverse functionalities, including chlorido, nitro, nitrile, and heteroatoms, and provides biaryls in appreciable yields. A practical, room-temperature nickel(III) catalytic system has been developed for the synthesis of biaryls in one step from the homocoupling of in situ generated Grignard reagents. The use of molecular oxygen as the oxidant makes the system environmentally friendly. The reaction system is compatible with diverse functionalities and affords biaryls in appreciable yields. Copyright
- Bhat, Aparna P. I.,Inam, Fawad,Bhat, Badekai Ramachandra
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- Unexpected golden Ullmann reaction catalyzed by Au nanoparticles supported on periodic mesoporous organosilica (PMO)
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We demonstrated an unprecedented example of Ullmann homocoupling reaction of aryl iodides over a novel recyclable gold catalyst comprising Au nanoparticles supported on a bifunctional periodic mesoporous organosilica (Au@PMO).
- Karimi, Babak,Kabiri Esfahani, Farhad
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- Gold/palladium bimetallic alloy nanoclusters stabilized by chitosan as highly efficient and selective catalysts for homocoupling of arylboronic acid
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Aerobic oxidative homocoupling of arylboronic acid under acidic aqueous conditions (pH 4.0) using bimetallic Au/Pd alloy nanoclusters stabilized by chitosan has been investigated. It was found that a Au0.81Pd 0.19 catalyst (3.1±0.8nm) exhibited superior catalytic activities as compared to monometallic Au (2.30.3nm) and other series of bimetallic nanoclusters, giving the corresponding biaryls in nearly quantitative yield.
- Sophiphun, Onsulang,Wittayakun, Jatuporn,Dhital, Raghu Nath,Haesuwannakij, Setsiri,Sakurai, Hidehiro,Murugadoss, Arumugam
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- Borylation of Aryldiazonium Ions with N-Heterocyclic Carbene-Palladium Catalysts Formed without Added Base
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(Matrix presented) A highly efficient catalytic borylation process with aryldiazonium ions was developed using a carbene-palladium catalyst formed in situ to give arylpinacolatoborane products. An X-ray structure for the N-heterocyclic carbene-palladium complex, used as the catalyst formed from bis(2,6-diisopropylphenyl)-4,5-dihydroimidazolium chloride, was obtained without added base.
- Ma, Yudao,Song, Chun,Jiang, Wei,Xue, Guoping,Cannon, John F.,Wang, Xiaomei,Andrus, Merritt B.
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- Encapsulated Gold Nanoparticles as a Reactive Quasi-Homogeneous Catalyst in Base-Free Aerobic Homocoupling Reactions
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Multiple gold nanoparticles (AuNPs) are physically encapsulated within a poly(N-isopropylacrylamide) particle at room temperature by an in situ reduction method using trisodium citrate (Cit) and sodium oxalate (Oxa) to serve as quasi-homogeneous catalysts for carbon?carbon bond-forming reactions under base-free aerobic conditions. The use of Oxa results in a more rapid formation and higher loading of AuNPs within the polymer particles compared to those prepared with conventional Cit. Upon dispersing both composite particles in EtOH-rich aqueous solvents, the polymer matrices maintain a fully swollen structure while still providing great stability to the AuNPs whose surfaces are analyzed to be nearly free from the reducing/stabilizing agents. As a catalyst in homocoupling reactions, the composite particles prepared with Oxa exhibit higher activity, selectivity, and recyclability with a much lower activation energy than those prepared with Cit. The preparation of the composite particles and their catalytic properties are optimized under environmentally-friendly reaction conditions, and the relationship between structural features and catalytic functions are examined to potentially develop robust, versatile, and green catalytic systems.
- Jang, Wongi,Byun, Hongsik,Kim, Jun-Hyun
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- Diquat derivatives, a precursor of organic reductant
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Electroreduction of diquat triflate gave a potent organic reductant, which promoted reductive dimerization of aryl bromides in the presence of palladium catalysts to give the corresponding biaryl compounds.
- Kuroboshi, Manabu,Kondo, Takashi,Tanaka, Hideo
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- Ultrasound induced, copper mediated homocoupling using polymer supported aryltrifluoroborates
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Using Dowex polymer supported aryltrifluoroborates, we are able to achieve homocoupling for a variety of compounds. The reactions were completed in 6 h, while producing high yields of the desired products. The reaction proceeds under mild conditions, using ultrasound as the energy source, copper acetate as the metal co-reactant, and aqueous ethanol as solvent.
- Musolino, Bryan,Quinn, Michael,Hall, Kelly,Coltuclu, Vitali,Kabalka, George W.
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- Nickel- and Palladium-Catalyzed Cross-Coupling of Stibines with Organic Halides: Site-Selective Sequential Reactions with Polyhalogenated Arenes
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Herein, we disclose a general and efficient method for the synthesis of Sb-aryl and Sb-alkyl stibines by the nickel-catalyzed cross-coupling of halostibines with organic halides. The synthesized Sb-aryl stibines couple with aryl halides to give biaryls efficiently via palladium catalysis. Sequential reactions of stibines with polyhalogenated arenes bearing active C–I/C–Br sites and inactive C–Cl sites successfully proceeded, resulting in the formation of a variety of complex molecules with good site selectivity. Drugs such as diflunisal and fenbufen, as well as a fenofibrate derivative, were synthesized on gram scales in good yields, together with the high recovery of chlorostibine. Furthermore, catalytic mechanisms are proposed based on the results of control experiments.
- Ghaderi, Arash,Kambe, Nobuaki,Le, Liyuan,Lu, Hao,Qiu, Renhua,Tang, Ting,Tong, Zhou,Wong, Wai-Yeung,Xu, Zhi,Yin, Shuang-Feng,Zeng, Dishu,Zhang, Dejiang,Zhang, Zhao
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p. 854 - 867
(2022/01/19)
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- Reductive Coupling of Aryl Halides via C—H Activation of Indene
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This paper describes the first case of a reductive coupling reaction with indene, a non-heteroatom olefin used as a reducing agent. The scope of the substrate is wide. The homo-coupling, cross-coupling, and synthesis of 12 and 14-membered rings were realized. The control experiment, indene-product curve and density functional theory calculations showed that the η3-palladium indene intermediate was formed by C—H activation in the presence of cesium carbonate. We speculate that the final product was obtained through a Pd (IV) intermediate or aryl ligand exchange. In addition, we excluded the formation of palladium anion (Pd(0)?) intermediates.
- Zhang, Bo-Sheng,Yang, Ying-Hui,Wang, Fan,Gou, Xue-Ya,Wang, Xi-Cun,Liang, Yong-Min,Li, Yuke,Quan, Zheng-Jun
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p. 1573 - 1579
(2021/05/28)
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- Zirconium-redox-shuttled cross-electrophile coupling of aromatic and heteroaromatic halides
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Transition metal-catalyzed cross-electrophile coupling (XEC) is a powerful tool for forging C(sp2)–C(sp2) bonds in biaryl molecules from abundant aromatic halides. While the synthesis of unsymmetrical biaryl compounds through multimetallic XEC is of high synthetic value, the selective XEC of two heteroaromatic halides remains elusive and challenging. Herein, we report a homogeneous XEC method, which relies on a zirconaaziridine complex as a shuttle for dual palladium-catalyzed processes. The zirconaaziridine-mediated palladium (ZAPd)-catalyzed reaction shows excellent compatibility with various functional groups and diverse heteroaromatic scaffolds. In accord with density functional theory (DFT) calculations, a redox transmetallation between the oxidative addition product and the zirconaaziridine is proposed as the crucial elementary step. Thus, cross-coupling selectivity using a single transition metal catalyst is controlled by the relative rate of oxidative addition of Pd(0) into the aromatic halide. Overall, the concept of a combined reducing and transmetallating agent offers opportunities for the development of transition metal reductive coupling catalysis.
- Fu, Yue,Liu, Fang-Jie,Liu, Peng,Tang, Jian-Tao,Toste, F. Dean,Wu, Ting-Feng,Ye, Baihua,Zhang, Yue-Jiao
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supporting information
p. 1963 - 1974
(2021/07/07)
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- Cobalt-catalyzed cross-coupling reactions of aryl- And alkylaluminum derivatives with (hetero)aryl and alkyl bromides
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A simple cobalt complex, such as Co(phen)Cl2, turned out to be a highly efficient and cheap precatalyst for a host of cross-coupling reactions involving aromatic and aliphatic organoaluminum reagents with aryl, heteroaryl and alkyl bromides. New C(sp2)-C(sp2) and C(sp2)-C(sp3) bonds were formed in good to excellent yields and with high chemoselectivity, under mild reaction conditions.
- Dilauro, Giuseppe,Messa, Francesco,Bona, Fabio,Perrone, Serena,Salomone, Antonio
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supporting information
p. 10564 - 10567
(2021/10/19)
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- A Ball-Milling-Enabled Cross-Electrophile Coupling
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The nickel-catalyzed cross-electrophile coupling of aryl halides and alkyl halides enabled by ball-milling is herein described. Under a mechanochemical manifold, the reductive C-C bond formation was achieved in the absence of bulk solvent and air/moisture sensitive setups, in reaction times of 2 h. The mechanical action provided by ball milling permits the use of a range of zinc sources to turnover the nickel catalytic cycle, enabling the synthesis of 28 cross-electrophile coupled products.
- Jones, Andrew C.,Nicholson, William I.,Leitch, Jamie A.,Browne, Duncan L.
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supporting information
p. 6337 - 6341
(2021/08/23)
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- Visible-Light-Promoted Metal-Free Synthesis of (Hetero)Aromatic Nitriles from C(sp3)?H Bonds**
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The metal-free activation of C(sp3)?H bonds to value-added products is of paramount importance in organic synthesis. We report the use of the commercially available organic dye 2,4,6-triphenylpyrylium tetrafluoroborate (TPP) for the conversion of methylarenes to the corresponding aryl nitriles via a photocatalytic process. Applying this methodology, a variety of cyanobenzenes have been synthesized in good to excellent yield under metal- and cyanide-free conditions. We demonstrate the scope of the method with over 50 examples including late-stage functionalization of drug molecules (celecoxib) and complex structures such as l-menthol, amino acids, and cholesterol derivatives. Furthermore, the presented synthetic protocol is applicable for gram-scale reactions. In addition to methylarenes, selected examples for the cyanation of aldehydes, alcohols and oximes are demonstrated as well. Detailed mechanistic investigations have been carried out using time-resolved luminescence quenching studies, control experiments, and NMR spectroscopy as well as kinetic studies, all supporting the proposed catalytic cycle.
- Murugesan, Kathiravan,Donabauer, Karsten,K?nig, Burkhard
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supporting information
p. 2439 - 2445
(2020/12/07)
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- Identification of a Surprising Boronic Acid Homocoupling Process in Suzuki-Miyaura Cross-Coupling Reactions Utilizing a Hindered Fluorinated Arene
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The Suzuki-Miyaura cross-coupling reaction of 2-bromo-1,3-bis(trifluoromethyl)benzene with arylboronic acids was evaluated and determined to suffer from the formation of large amounts of boronic acid homocoupling products in conjunction with dehalogenation. Homocoupling product formation in this process likely occurs through a rare protonolysis/second transmetalation event rather than by the well-established mechanism requiring the involvement of O 2. The scope of this boronic acid homocoupling reaction was investigated and shown to predominate with electron-deficient arylboronic acids. Finally, a good yield of cross-coupling products could be obtained by employing dicyclohexyl(2′,6′-dimethoxybiphenyl-2-yl)phosphine (SPhos) as the ligand.
- Gargaro, Samantha L.,Dunson, Bre'Shon,Sieber, Joshua D.
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supporting information
p. 511 - 516
(2020/09/21)
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- Rigid Conjugated Diamine Templates for Stable Dion-Jacobson-Type Two-Dimensional Perovskites
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Hybrid organic-inorganic perovskites (HOIPs) have garnered widespread interest, yet stability remains a critical issue that limits their further application. Compared to their three-dimensional (3D) counterparts, two-dimensional (2D)-HOIPs exhibit improved stability. 2D-HOIPs are also appealing because their structural and optical properties can be tuned according to the choice of organic ligand, with monovalent or divalent ligands forming Ruddlesden-Popper (RP) or Dion-Jacobson (DJ)-type 2D perovskites, respectively. Unlike RP-type 2D perovskites, DJ-type 2D perovskites do not contain a van der Waals gap between the 2D layers, leading to improved stability. However, bifunctional organic ligands currently used to develop DJ-type 2D perovskites are limited to commercially available aliphatic and single-ring aromatic ammonium cations. Large conjugated organic ligands are in demand for their semiconducting properties and their potential to improve materials stability further. In this manuscript, we report the design and synthesis of a new set of larger conjugated diamine ligands and their incorporation into DJ-type 2D perovskites. Compared with analogous RP-type 2D perovskites, DJ 2D perovskites reported here show blue-shifted, narrower emissions and significantly improved stability. By changing the structure of rings (benzene vs thiophene) and substituents, we develop structure-property relationships, finding that fluorine substitution enhances crystallinity. Single-crystal structure analysis and density functional theory calculations indicate that these changes are due to strong electrostatic interactions between the organic templates and inorganic layers as well as the rigid backbone and strong π-πinteraction between the organic ligands themselves. These results illustrate that targeted engineering of the diamine ligands can enhance the stability of DJ-type 2D perovskites.
- Zhao, Ruyan,Sabatini, Randy P.,Zhu, Tong,Wang, Sasa,Morteza Najjarian, Amin,Johnston, Andrew,Lough, Alan J.,Hoogland, Sjoerd,Sargent, Edward H.,Seferos, Dwight S.
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supporting information
p. 19901 - 19908
(2021/11/30)
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- Sustainable Synthesis of Biaryls Using Silica Supported Ferrocene Appended N-Heterocyclic Carbene-Palladium Complex
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Abstract: A novel silica supported ferrocene appended N-heterocyclic carbene-palladium complex (SilFemBenzNHC@Pd) has been prepared and characterized by using fourier transform infrared (FT-IR), fourier transform Raman (FT-Raman), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and energy dispersive X-ray analysis (EDX). This novel complex served as a robust heterogeneous catalyst for the synthesis of biaryls via homocoupling of aryl boronic acids under base-free conditions in water. Recyclability experiments were executed successfully for six successive runs. Graphic Abstract: [Figure not available: see fulltext.]
- Khanapure, Sharanabasappa,Pore, Dattaprasad,Jagadale, Megha,Patil, Vaishali,Rashinkar, Gajanan
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p. 2237 - 2249
(2021/01/11)
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- Exploring the coordination confinement effect of divalent palladium/zero palladium doped polyaniline-networking: As an excellent-performance nanocomposite catalyst for C-C coupling reactions
-
A pre-formed catalyst Pd2+/PANI composite for C-C coupling reaction was synthesized by combining the self-stabilized dispersion polymerization method with the in-situ composite material. Experiments have confirmed that the relatively high reduced structure (75%) in the polyaniline carrier is more favorable for the coupling reaction. Raman spectroscopy, solid nuclear magnetic, and X-ray photoelectron spectroscopy were performed to characterize the structures. The pre-formed catalyst has uniform coordination of divalent palladium and nitrogen in different valence states of the carrier polyaniline, which shows a good synergistic effect in the catalytic Ullmann reaction, and greatly reduces the use of reducing agents such as hydrazine hydrate. Compared with other studies, we analyzed the catalytic reaction mechanism in detail through real-time online infrared and XPS characterization. The results show that the divalent palladium in the catalyst and the zero-valent palladium generated by the in-situ reaction synergistically promote the reaction, while the polyaniline support acts as a stabilizer and dispersant, which prevents the agglomeration of the metal particles and prolongs increased catalyst life. The prepared Pd2+/PANI composites will become the most attractive alternative to traditional organic materials due to their wide applicability, high catalytic activity, stable recycling and relatively low price. This work provides a new theoretical basis for the understanding of the essential driving force of PANI catalytic activity and the cognition of the micro mechanism of action.
- Liang, Yanping,Liu, Wanyi,Song, Manrong,Sun, Yanyan,Wang, Gang,Wu, Zhiqiang,Zhan, Haijuan
-
p. 177 - 188
(2020/03/17)
-
- A Bio-Inspired Magnetically Recoverable Palladium Nanocatalyst for the Ullmann Coupling reaction of Aryl halides and Arylboronic acids In Aqueous Media
-
Palladium nanoparticles supported on polydopamine-coated iron oxide nanoparticles (Pd/Fe3O4@PDA) were found to catalyze the Ullmann homocoupling of a wide variety of aryl halides, arylboronic acids and aryldiazonium salts in aqueous media in the presence of randomly methylated β-cyclodextrin (RM-β-CD). The synthesized nanoparticles were characterized by techniques such as TEM, SEM, EDX, XPS, ICP-AES and XRD. The synthesized catalyst can be easily recovered magnetically and reused up to five cycles without any significant loss of activity. This is the first report demonstrating the use of magnetically recoverable catalyst for Ullmann homocoupling reactions of aryl halides, arylboronic acids and aryldiazonium salts in water.
- Dubey, Abhishek V.,Kumar, A. Vijay
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- Palladium/Sensory Component-Catalyzed Homocoupling Reactions of Aryl Halides
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A novel and efficient catalyst system was developed for homocoupling reactions of aryl halides. The catalyst system consists of Pd(OAc) 2and the peppery sensory component of tobacco leaves. This is the first time that a sensory component has been used in an organic reaction. Experiments using the catalyst system showed that the reactions proceeded smoothly under air in the absence of both an additional ligand and a reductant. Furthermore, the catalyst system can be applied to the coupling reactions of hetaryl iodides. Many functional groups (including a hydroxy group) are tolerated.
- Bai, Haixin,Bao, Fengyu,Chai, Guobi,Liu, Pengfei,Liu, Zhikai,Zhang, Haiyan,Zhang, Qidong
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supporting information
(2020/09/09)
-
- The cyano group of the aromatic compound production (by machine translation)
-
[Problem] to reduce toxicity, treatment after reaction is easy, and a high selectivity, a manufacturing method of an aromatic nitrile compound. [Solution] the formula illustrated, unsubstituted or substituted with electron donating groups 1a and aromatic halogen compounds, cyanide 4 · quaternary ammonium nitrile with a second agent, a transition metal-free catalyst phenanthroline compound, such as dimethyl sulfoxide with a mixture containing an aprotic organic solvent, the reaction temperature range of the reaction is heated to 110 c 180 °C cyano, aromatic nitrile compound 2a of production. [Drawing] no (by machine translation)
- -
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Paragraph 0129-0132; 0163-0167; 0183-0187
(2020/05/14)
-
- Dehydrogenation of Primary Alkyl Azides to Nitriles Catalyzed by Pincer Iridium/Ruthenium Complexes
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Pincer metal complexes exhibit superior catalytic activity in the dehydrogenation of plain alkanes, but find limited application in the dehydrogenation of functionalized organic molecules. Starting from easily accessible primary alkyl azides, here we report an efficient dehydrogenation of azides to nitriles using pincer iridium or ruthenium complexes as the catalysts. This method offers a route to cyanide-free preparation of nitriles without carbon chain elongation and without the use of strong oxidants. Both benzyl and linear aliphatic azides can be dehydrogenated with tert-butylethylene as the hydrogen acceptor to afford nitriles in moderate to high yields. Various functional groups can be tolerated, and the H?C?C?H bond dehydrogenation does not occur for linear alkyl azide substrates. Furthermore, the pincer Ir catalytic system was found to catalyze the direct azide dehydrogenation without the use of a sacrificial hydrogen acceptor.
- Gan, Lan,Jia, Xiangqing,Fang, Huaquan,Liu, Guixia,Huang, Zheng
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p. 3661 - 3665
(2020/06/02)
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- Glucopyranoside-substituted imidazolium-based chiral ionic liquids for Pd-catalyzed homo-coupling of arylboronic acids in water
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Chiral ionic liquids (CILs) are widely used solvents and materials with prominent properties. Carbohydrate-derived imidazolium-based CILs represent a distinctive type of CILs possessing multiple chiral centers from natural chiral pool. Herein, a series of glucopyranoside-substituted imidazolium-based CILs (Glu-imi-CILs) were synthesized and evaluated as ligands for Pd-catalyzed homo-coupling reactions of arylboronic acids in water. The glucopyranoside substituent was instrumental for improving the catalytic activity of the resulting catalysts. Moreover, a Glu-imi-CIL with a free hydroxyl group for additional coordination was found to be the most efficient ligand. A series of symmetric biaryl compounds (13 examples) were synthesized from arylboronic acids by this method in high isolated yields (85?99percent).
- Huang, Zhiqiang,Kong, Lingfang,Li, Jing,Wu, Yue,Xue, Jun,Yuan, Yangyang,Zhou, Zhonggao
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-
- Synthesis method of biphenyl compounds
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The invention discloses a synthesis method of biphenyl compounds. The synthesis method comprises the following steps: by using an aromatic boric acid as a reaction substrate and palladium as a catalyst, adding a catalytic amount of a phase transfer catalyst, reacting in a sodium hypochlorite water solution at 50 DEG C for 1-5 hours, carrying out oxidative coupling, and carrying out post-reaction treatment to obtain a target product biphenyl compound. The method has the characteristics of mild reaction conditions, simplicity in operation and purification, wide substrate application range, highyield, high reaction speed and the like, and has practicability.
- -
-
Paragraph 0152-0169
(2020/02/06)
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- Palladium Ion Catalysed Oxidative C–C Bond Formation Reactions in Arylboronic Acid: Application of Cordierite Monolith Coated Catalyst
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Abstract: Catalytic efficiency of palladium ion substituted in TiO2, Ti0.97Pd0.03O1.97 is successfully exploited for the oxidative homocoupling of arylboronic acid and oxidative Heck coupling reactions between arylboronic acid and olefins. The reaction protocol provides direct approach to synthesize biphenyls and cinnamates from moderate to good yield with good functional group tolerance. As a result, 11 symmetrical biaryls and 14 cinnamates were synthesized from readily available arylboronic acids. Ti0.97Pd0.03O1.97 powder catalyst is synthesized by solution combustion method and characterized by powder X-ray diffraction. The C–C bond formation reactions were carried out by catalyst cartridge method using Ti0.97Pd0.03O1.97 catalyst coated cordierite monolith. Coating of the catalyst on a cordierite monolith enhanced the applicability of the catalyst and made handling and recycling of the catalyst very easy. Catalyst was recovered and recycled for eight times in both homocoupling and oxidative Heck coupling reactions. The turnover number for both the reactions found to be 443 and 424, respectively. Graphic Abstract: [Figure not available: see fulltext.].
- Bhat, Shrikanth K.,Prasanna,Dasappa, Jagadeesh Prasad,Hegde
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p. 2911 - 2927
(2020/03/31)
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- Efficient Pd-catalyzed oxidative homocoupling of arylboronic acids in aqueous NaClO
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An efficient, mild and practical method was developed for the synthesis of biaryls via the Pd-catalyzed oxidative homocoupling of aromatic/heteroaromatic boronic acids in aqueous NaClO.
- Li, Min-Xin,Tang, Yan-Ling,Gao, Hui,Mao, Ze-Wei
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supporting information
(2020/03/04)
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- Ligand-free palladium catalyzed Ullmann biaryl synthesis: 'Household' reagents and mild reaction conditions
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A palladium catalysed Ullmann biaryl synthesis has been developed using hydrazine hydrate as the reducing reagent at room temperature. The combination of Pd(OAc)2 and hydrazine hydrate works smoothly for the coupling of both electron-rich and electron-deficient aryl iodides, as well as hetero-aryl iodides, leading to a wide range of biaryls in good to excellent yields. The reaction requires only 1 mol% Pd(OAc)2 and the in situ generated palladium naoparticles are found to be active catalysts.
- Gong, Xinchi,Wu, Jie,Meng, Yunge,Zhang, Yulan,Ye, Long-Wu,Zhu, Chunyin
-
supporting information
p. 995 - 999
(2019/03/12)
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- Copper-catalyzed Mizoroki-Heck coupling reaction using an efficient and magnetically reusable Fe3O4@SiO2@PrNCu catalyst
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This study intends to design and prepare a new magnetic copper catalyst and its activity was assessed by carbon-carbon coupling reactions. For this purpose, 1-[3-(trimethoxysilyl) propyl] urea (TMSPU), hydrazine and CuI were used sequentially to modify Fe3O4@SiO2 core-shell magnetic nanoparticles to obtain an efficient magnetic transition metal catalyst. Various analytical techniques were used to characterize the catalyst to show that the achieved structure and its properties are well-suited for coupling reactions. Finally, Mizoroki-Heck and Ullmann coupling reactions were performed using Fe3O4@SiO2@PrNCu catalyst. The new catalyst offer simple synthetic procedure, convenient use for routine casework and low price. The Fe3O4@SiO2@PrNCu catalyst was easily separated by means of a permanent and ordinary magnet and the recovered catalyst was reused in six cycles without any significant loss of activity.
- Yavari, Issa,Mobaraki, Akbar,Hosseinzadeh, Zhila,Sakhaee, Nader
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supporting information
p. 236 - 246
(2019/07/19)
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- PdAu alloy nanoparticles supported on nitrogen-doped carbon black as highly active catalysts for Ullmann coupling and nitrophenol hydrogenation reactions
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Noble metal-based catalysts have been proven to be active for catalytic organic reactions. The selectivity and conversion can be improved by integration with proper carrier materials, and further modulated by tuning the composition as well as the electronic structure of the active noble metals. Compared with unsupported monometallic catalysts, the synergistic interactions between neighboring metals and the combined effects between the carrier materials and the active components often give rise to positive influences on the enhancement of the catalytic efficiency and selectivity. In this work, we report a facile process for the fabrication of nitrogen-doped carbon black (NCB) supported PdAu bimetallic nanoparticles (NPs) with a uniform dispersion and narrow size distribution. The PdAu/NCB catalyst with a Pd/Au mole ratio of 1/1 shows the highest activity towards both Ullmann coupling reactions of aryl halides and the hydrogenation reaction of nitrophenols. Moreover, this bimetallic catalyst also exhibits a superior recycling durability to that of monometallic Pd/NCB and Au/NCB catalysts. The enhanced catalytic performance of the bimetallic catalyst is mainly due to the large BET specific surface area (125.45 m2 g-1) and the synergy between the individual components of the catalyst.
- Han, Fengyan,Xia, Jiawei,Zhang, Xinglong,Fu, Yongsheng
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p. 17812 - 17823
(2019/06/24)
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- Photocatalytic coupled redox cycle for two organic transformations over Pd/carbon nitride composites
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Heterogeneous photocatalysis offers a means for "green" organic transformations. Generally, photogenerated electrons and holes are not utilized simultaneously and effectively. Here we report a coupling approach to promote simultaneously two organic transformations of the Ullmann C-C coupling reaction and the value-added aromatic alcohol oxidation reaction in inert solvent and under anaerobic conditions using a carbon nitride based composite (Pd/CN-450) prepared by loading Pd nanoparticles (NPs) on CN-450 (N defect and O dopant co-modified g-C3N4 with high crystallinity). Upon photo-excitation of the photocatalyst, the activation of carbon-halogen bonds of the adsorbed aryl halides can be promoted by the photogenerated electrons on Pd NPs and the aromatic alcohols undergo dissociation and dehydrogenation, and finally can be oxidized by the captured photogenerated holes from CN-450 in the presence of a Br?nsted base. N defects, O doping, and improved crystallinity, controlled by changing the post-annealing temperature in molten salts, enhance the visible light absorption and improve charger carrier separation of the functionalized carbon nitride. The smaller size and high dispersity of Pd NPs give the higher surface area-to-volume ratio resulting in efficient adsorption and activation of reactant molecules on Pd NPs and allow for the effective interfacial interaction of CN-450 with Pd NPs for promoting electron transfer from CN-450 to Pd NPs. As a result, Pd/CN-450 displays a superior photocatalytic activity of the coupled reaction compared to Pd/g-C3N4 (Pd NP supported pristine g-C3N4). Moreover, the coupled reaction system has general applicability for various substrates and shows reusability.
- Jia, Qiaohui,Zhang, Sufen,Jia, Xiaoxia,Dong, Xiaoyang,Gao, Ziwei,Gu, Quan
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p. 5077 - 5089
(2019/10/05)
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- Preparing method of aromatic nitrile or alkenyl nitrile compound
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The invention discloses a preparing method of an aromatic nitrile or alkenyl nitrile compound. The preparing method comprises the following step that under protection of inert gas, an aryl or heteroaryl sulphonate compound shown in a formula II or an alkenyl sulphonate compound shown in a formula IV and a cyanation reagent are subjected to a cross-coupling reaction as is shown below in a solvent under the condition of the presence of a nickel complex, metal zinc and an additive to obtain the aromatic nitrile or alkenyl nitrile compound, wherein 4-dimethylamiopryidine (DMAP) is adopted as the additive, and zinc cyanide is adopted as the cyanation reagent. By means of the preparing method, cyanation of aryl sulphonate, heteroaryl sulphonate or alkenyl sulphonate can be simply and efficientlyachieved with a cheap catalysis system; moreover, the functional group compatibility and substrate universality are good, and a better application prospect and higher using value are provided for achieving industrial synthesis of the aromatic nitrile or alkenyl nitrile compound.
- -
-
Paragraph 0130-0132; 0196-0198; 0232-0233
(2019/10/01)
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- Synergistic Activities in the Ullmann Coupling of Chloroarenes at Ambient Temperature by Pd-Supported Calcined Ferrocenated La2O3
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Novel palladium-doped nanoparticles have been explored to serve as the first metal oxide-derived heterogeneous catalyst for Ullmann reaction of chloroarenes under mild condition (34?°C). This heterogeneous catalyst exhibited high catalytic activity towards the Ullmann homocoupling of chloroarenes into a series of useful symmetrically biaryl products with good to excellent yields in the presence of ethanol and NaOH, thereby leading to green and economical Ullmann reaction. The produced nanoparticles were successfully characterized by various techniques including PXRD, XPS, HRTEM, SEM-EDS, BET, TGA techniques, elemental mapping analysis and ICP-OES. Interestingly, based on characterization and experimental data, a reasonable mechanism has been proposed. Also, the formation of aryl methyl ketone as a by-product has been further confirmed by isotopic labelling experiments that the acetyl moiety is derived from ethanol. Moreover, the catalyst was stable and could be easily reused up to 5 times under atmospheric air without suffering significant loss in catalytic activity.
- Chumkaeo, Peerapong,Poonsawat, Thinnaphat,Meechai, Titiya,Somsook, Ekasith
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- 1,10-Phenanthroline- or Electron-Promoted Cyanation of Aryl Iodides
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A 1,10-phenanthroline-promoted cyanation of aryl iodides has been developed. 1,10-Phenanthroline worked as an organocatalyst for the reaction of aryl iodides with tetraalkylammonium cyanide to afford aryl cyanides. A similar reaction occurred through an electroreductive process.
- Hirata, Takayuki,Mandai, Hiroki,Midorikawa, Koji,Mitsudo, Koichi,Suga, Seiji,Yoshioka, Kazuki
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supporting information
p. 1209 - 1214
(2019/06/08)
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- Ni-Catalyzed Reductive Cyanation of Aryl Halides and Phenol Derivatives via Transnitrilation
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Herein, we report a Ni-catalyzed reductive coupling for the synthesis of benzonitriles from aryl (pseudo)halides and an electrophilic cyanating reagent, 2-methyl-2-phenyl malononitrile (MPMN). MPMN is a bench-stable, carbon-bound electrophilic CN reagent that does not release cyanide under the reaction conditions. A variety of medicinally relevant benzonitriles can be made in good yields. Addition of NaBr to the reaction mixture allows for the use of more challenging aryl electrophiles such as aryl chlorides, tosylates, and triflates. Mechanistic investigations suggest that NaBr plays a role in facilitating oxidative addition with these substrates.
- Mills, L. Reginald,Graham, Joshua M.,Patel, Purvish,Rousseaux, Sophie A. L.
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supporting information
p. 19257 - 19262
(2019/12/02)
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- Transformation of aromatic bromides into aromatic nitriles with n-BuLi, pivalonitrile, and iodine under metal cyanide-free conditions
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Various aromatic nitriles could be obtained in good yields by the treatment of aryl bromides with n-butyllithium and then pivalonitrile, followed by the treatment with molecular iodine at 70 °C, without metal cyanides under transition-metal-free conditions. The present reaction proceeds through the radical β-elimination of imino-nitrogen-centered radicals formed from the reactions of imines and N-iodoimines under warming conditions.
- Uchida, Ko,Togo, Hideo
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- Electrocarboxylation of halobenzonitriles: An environmentally friendly synthesis of phthalate derivatives
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This manuscript presents an efficient approach for producing high valuable compounds using CO2 as building block. The methodology employed is based on electrochemical techniques, which allow performing eco-friendly chemistry solutions and maintaining the aim of offering a potential long-term strategy for reducing the CO2 emissions in the atmosphere, while obtaining useful compounds, such as aromatic acids and phthalate derivatives. This work describes the electrochemical reduction behavior of 4-halobenzonitrile compounds using Glassy Carbon and Silver as cathodes under inert and carbon dioxide atmosphere. Controlled potential electrolysis of 4-halobenzonitriles under CO2 allows obtaining, in very good yields, the corresponding mono- and di-carboxylated organic compounds in CO2-saturated solutions of dimethylformamide containing 0.1 M of tetrabutylammonium tetrafluoroborate. Electro-catalytic effects are seen when Ag is used a cathode, which give very high yields, especially as regards di-carboxylated products. The methodology offers a new “green” route for the synthesis of different phthalate derivatives, which can be potentially used for making plastic polymers in a more environmentally friendly way.
- Reche, Irene,Mena, Silvia,Gallardo, Iluminada,Guirado, Gonzalo
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- Desulfurization of Diaryl(heteroaryl) Sulfoxides with Benzyne
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Two benzyne-enabled desulfurization reactions have been demonstrated which convert diaryl sulfoxides and heteroaryl sulfoxides to biaryls and desulfurized heteroarenes, respectively. The reaction accessing biaryls tolerates a variety of functional groups, such as halides, pseudohalides, and carbonyls. Mechanistic studies reveal that both reactions proceed via a common assembly process but divergent disassemblies of the generated tetraaryl(heteroaryl) sulfuranes.
- Chen, De-Li,Sun, Yan,Chen, Mengyuan,Li, Xiaojin,Zhang, Lei,Huang, Xin,Bai, Yihui,Luo, Fang,Peng, Bo
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supporting information
(2019/06/13)
-
- Method for directly synthesizing biarene compounds without metal catalysis
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The invention discloses a method for directly synthesizing biarene compounds without metal catalysis. The method is characterized in that one diaryl sulfoxide represented by a structural formula (I) shown in the description and trimethylsilyl phenyl trifluoromethanesulfonate represented by a structural formula (II) are subjected to a reaction in the presence of cesium fluoride to obtain one corresponding biarene compound represented by a formula (III) shown in the description. The method provided by the invention does not require to add any expensive metal catalyst during the reaction, therebyreducing the production costs; and the compounds have better compatibility with a substrate containing better leaving groups (such as halogen and OTs) on an aromatic ring.
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-
Paragraph 0045-0048
(2019/08/20)
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- Cascade Process for Direct Transformation of Aldehydes (RCHO) to Nitriles (RCN) Using Inorganic Reagents NH2OH/Na2CO3/SO2F2 in DMSO
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A simple, mild, and practical process for direct conversion of aldehydes to nitriles was developed feathering a wide substrate scope and great functional group tolerability (52 examples, over 90% yield in most cases) using inorganic reagents (NH2OH/Na2CO3/SO2F2) in DMSO. This method allows for transformations of readily available, inexpensive, and abundant aldehydes to highly valuable nitriles in a pot, atom, and step-economical manner without transition metals. This protocol will serve as a robust tool for the installation of cyano-moieties to complicated molecules.
- Fang, Wan-Yin,Qin, Hua-Li
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p. 5803 - 5812
(2019/05/14)
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- Salen-porphyrin-based conjugated microporous polymer supported Pd nanoparticles: Highly efficient heterogeneous catalysts for aqueous C-C coupling reactions
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The salen-porphyrin based conjugated microporous polymer (SP-CMP) was first constructed by polycondensation reaction of a salen-dialdehyde derivative and pyrrole. Due to the outstanding chemical and thermal stability, abundant micropores with a reasonable pore size, and ordered salen-porphyrin arrays in the A4B4-type polymer framework, the functional CMP was further applied as a Pd nanoparticle support by the coordinate interactions between the polydentate chelating sites with Pd(OAc)2 and subsequent reduction with NaBH4. The as-synthesized composite material (Pd@SP-CMP) was fully characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and solid-state 13C nuclear magnetic resonance (NMR). The porous property of Pd@SP-CMP was also characterized by N2 adsorption/desorption isotherms and the obtained material exhibited a Brunauer-Emmett-Teller (BET) surface area of 266 m2 g-1, together with a pore volume of 0.192 cm3 g-1. The microscopic morphology of Pd@SP-CMP was further evaluated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Pd@SP-CMP material with highly dispersed Pd nanoparticles exhibited excellent catalytic activity towards Suzuki-Miyaura and Heck-Mizoroki coupling reactions in water or in the dioxane/water mixture. In addition, Pd@SP-CMP also displayed outstanding stability and recyclability, and it can be reused without loss of activity in ten successive reactions. More importantly, the salen-porphyrin based CMPs could be the promising candidates for developing high-performance heterogeneous catalysts.
- Ju, Pengyao,Wu, Shujie,Su, Qing,Li, Xiaodong,Liu, Ziqian,Li, Guanghua,Wu, Qiaolin
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supporting information
p. 2660 - 2666
(2019/02/12)
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- Palladium Palladium Nanoparticles Nanoparticles Supported Supported on β-cyclodextrin on β-Cyclodextrin Functionalised Functionalized Poly(amido Poly(amidoamine)s amine)s and their and Application Their Application in Suzuki-Miyaura in Suzuki-Miyaura Cross-Coupling Cross-Coupling Reactions Reactions
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Herein, the synthesis, characterization and catalytic application of an organic-inorganic, palladium (Pd)-containing hybrid material, poly(amidoamine)-cyclodextrin (Pd@PAAs-CD), is reported as an efficient catalyst for Suzuki-Miyaura coupling reactions. The structure of Pd@PAAs-CD was confirmed by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), inductively-coupled plasma atomic emission spectroscopy (ICP-AES), and 1H nuclear magnetic resonance (NMR) spectroscopy. Furthermore, an efficient protocol has been developed using Pd@PAAs-CD as the catalyst in a Suzuki-Miyaura cross-coupling reaction in an aqueous medium in high yields. By using cyclodextrin (CD) as the mediator grafted onto PAAs, the Pd nanoparticles (NPs) were dispersed and enhanced the catalytic reaction by promoting host-guest interactions with the CD. In addition, the reusability of the Pd@PAAs-CD hybrid material is demonstrated for use in multiple sequential cross-coupling reactions.
- Zhang, Wei,Yao, Zi-Jian,Deng, Wei
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p. 1667 - 1677
(2019/10/01)
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- Aerobic Homocoupling of Arylboronic Acids Catalyzed by Regenerable Pd(II)@MIL-88B-NH2(Cr)
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A fast and operationally simple method for the aerobic homocoupling of arylboronic acids is described. The process is catalyzed by Pd(II) complexes supported on the metal-organic framework MIL-88B-NH2(Cr). The benefits of this approach include the use of a benign oxidant/solvent mixture at room temperature with catalytic amounts of base, easy recovery of the catalyst, and easy isolation of the products. Very high conversions and good yields were achieved for a variety of substrates, and the process was also carried out on a larger scale with the same efficiency. The catalyst was found to suffer deactivation due to progressive reduction and agglomeration of palladium into inactive metal clusters/particles. An innovative procedure for the oxidative redispersion and regeneration of the active Pd(II)@MOF species is presented.
- Valiente, Alejandro,Carrasco, Sergio,Sanz-Marco, Amparo,Tai, Cheuk-Wai,Bermejo Gómez, Antonio,Martín-Matute, Belén
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p. 3933 - 3940
(2019/05/22)
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- Au-Pd bimetallic nanoparticles supported on a high nitrogen-rich ordered mesoporous carbon as an efficient catalyst for room temperature Ullmann coupling of aryl chlorides in aqueous media
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An ionic liquid derived highly nitrogen-rich mesoporous carbon supported Au-Pd alloy was found to be an efficient and recyclable catalyst for the Ullmann coupling reaction of various aryl chlorides at room temperature in aqueous media.
- Karimi, Babak,Barzegar, Hossein,Vali, Hojatollah
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p. 7155 - 7158
(2018/07/05)
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- Nickel-Catalyzed Electrochemical Reductive Homocouplings of Aryl and Heteroaryl Halides: A Useful Route to Symmetrical Biaryls
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Due to their widespread presence in functional materials and pharmaceuticals, biaryls are of fundamental importance in organic chemistry. Methods for the synthesis of symmetrical biaryls generally involve both metallic reduction and transition-metal catalysis. In this work, we show that electroreduction can also constitute a very relevant way to achieve the nickel-catalyzed reductive synthesis of symmetrical biaryl compounds. Therefore, it is demonstrated that both aryl and heteroaryl halides undergo reductive coupling to furnish the corresponding symmetrical biaryls in fair to excellent yields. Reactions are performed under very mild conditions thus ensuring important functional group tolerance.
- Rahil, Rima,Sengmany, Stéphane,Le Gall, Erwan,Léonel, Eric
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p. 146 - 154
(2017/09/28)
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- Palladium-mediated radical homocoupling reactions: A surface catalytic insight
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In this contribution, we report a palladium nanoparticle-promoted reductive homocoupling of haloarenes that proceeds efficiently to produce corresponding bis-aryls in moderate to excellent yields using relatively low catalyst loading (1 mol%), and exhibits broad functional group tolerance. This work sheds light on how the surface state of Pd(0) nanoparticles plays a crucial role in the reactivity of catalytic systems. Notably, the appropriate choice of palladium salts for the preparation of the preformed nanocatalysts was a key parameter having a major impact on the catalytic activity; thus, the effect of halide anions on the reactivity of the as-prepared palladium nanoparticles could be assessed, with iodide anions being capable of inhibiting the corresponding homocoupling reaction. The homocoupling reaction mechanism has been further studied by means of radical trap and electron paramagnetic resonance (EPR) experiments, revealing that the reaction proceeds via radical intermediates. Taking into account these data, a plausible reaction mechanism based on single-electron transfer processes on the palladium nanoparticle surface is discussed.
- Favier, Isabelle,Toro, Marie-Lou,Lecante, Pierre,Pla, Daniel,Gómez, Montserrat
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p. 4766 - 4773
(2018/09/29)
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- Immobilization of an Aminobisphosphine–PdII Complex over Graphene Oxide: An Efficient and Reusable Catalyst for Suzuki–Miyaura, Ullmann Coupling and Cyanation Reactions
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The grafting of an aminobis(phosphine)–PdII complex (PNP–PdII) [PdCl2{(Ph2P)2N(CH2)3Si(OMe)3}] (2) on graphene oxide (GO) has been carried out by a condensation reaction between methoxysilane groups of 2 and hydroxyl groups of GO. The composite material was characterized by FTIR spectroscopy, solid-state 31P NMR spectroscopy, SEM, TEM, XPS and ICP-AES techniques. All these tools support the clean immobilization of compound 2 on GO. The composite material showed high catalytic activity in Suzuki–Miyaura, Ullmann coupling and cyanation reactions. The heterogeneity of the composite was confirmed by a hot filtration test. The immobilized PNP–PdII shows comparable activity to its homogeneous analogue 2. The recycling ability of the catalyst was examined for five consecutive runs, which showed little or no reduction in its catalytic efficiency.
- Sengupta, Debasish,Pandey, Madhusudan K.,Mondal, Dipanjan,Radhakrishna, Latchupatula,Balakrishna, Maravanji S.
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p. 3374 - 3383
(2018/05/08)
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- Palladium nanocatalysts in glycerol: Tuning the reactivity by effect of the stabilizer
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Palladium nanoparticles (PdNPs) prepared in neat glycerol containing TPPTS (tris(3-sulfophenyl)phosphine trisodium salt) or cinchona-based alkaloids (cinchonidine, quinidine) as capping agents, were applied as catalysts in fluoride-free Hiyama couplings and conjugate additions with the aim of evaluating the influence of the stabilizer in the catalytic reactivity. Therefore, PdNPs stabilized by phosphine favored C–C cross-couplings, whereas those containing alkaloids showed enhanced suitability for C–C homo-couplings and conjugate additions. The metal/stabilizer coordination mode, i.e. Pd–P dative bond and π-π interaction between quinoline moiety and palladium surface, is certainly key for the stabilization of different active metallic species and then promoting distinctive catalytic pathways.
- Reina, Antonio,Serrano-Maldonado, Alejandro,Teuma, Emmanuelle,Martin, Erika,Gómez, Montserrat
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- Oxidative and Reductive Cross-Coupling Reactions Catalyzed by an Anionic "ligandless" Palladium Complex
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The anionic complex [NBu4][Pd(DMSO)Cl3], which can be synthesized on a gram scale in a single step starting from commercially available starting materials, has been shown to be an active catalyst in the Mizoroki-Heck reaction of aryl halides. We present two new catalytic applications of this complex: the base-free oxidative Heck reaction and the reductive homodimerization of aryl halides. This complex outperformed other palladium salts. In the latter reaction, the catalyst loading could be reduced to 0.01 mol %. The scope of the reactions has been explored, demonstrating the potential of the anionic palladium complex in these catalytic transformations.
- Schroeter, Felix,Lerch, Swantje,Strassner, Thomas
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supporting information
p. 1614 - 1621
(2019/01/04)
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- Nickel-Catalyzed Cyanation of Phenol Derivatives with Zn(CN)2 Involving C-O Bond Cleavage
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An efficient nickel-catalyzed cyanation of aryl sulfonates, fluorosulfonates, and sulfamates with Zn(CN)2 was developed, which provides a facile access to the nitrile products in generally good to excellent yields. The reaction is accomplished by using NiII complex as the precatalyst and DMAP as the additive. The method also displays wide functional group compatibility; for example, keto, methoxy, N,N-dimethylamino, cyano, ester, and pyridyl groups are well-tolerated during the reaction process.
- Gan, Yi,Wang, Gaonan,Xie, Xin,Liu, Yuanhong
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p. 14036 - 14048
(2018/11/03)
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- Synthesis of dendrimer-type viologen and its use in Pd-mediated homocoupling of aryl halides
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Dendrimer-type viologen (V2+.D.) was prepared from mesitylene and 4.4′-bipyridyl. Electroreduction of V2+.D. gave the corresponding quinoid (V0.D.), which promoted Pd-catalyzed homocoupling of aryl bromides Ar-Br to give the corresponding biaryls Ar-Ar in moderate to good yields.
- Kuroboshi, Manabu,Kojima, Atsuki,Tanaka, Hideo
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p. 2132 - 2140
(2017/11/21)
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- Photocatalyst-free, Visible Light Driven, Gold Promoted Suzuki Synthesis of (Hetero)biaryls
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A visible-light driven Suzuki cross-coupling reaction was performed with colored and bench-stable arylazosulfones in the presence of Ph3PAuCl (5 mol %) as the catalyst. The absence of a photocatalyst, along with the use of commercially available and easy-to-handle arylboronic acids underline the novelty and synthetic usefulness of the protocol. A reaction mechanism involving the generation of an aryl radical as the key intermediate has been proposed on the basis of experimental investigations.
- Sauer, Christopher,Liu, Yang,De Nisi, Assunta,Protti, Stefano,Fagnoni, Maurizio,Bandini, Marco
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p. 4456 - 4459
(2017/11/20)
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- Palladium-catalyzed reductive homocoupling of aryl sulfonates via cleavage of C─O bond at room temperature
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Palladium-catalyzed reductive homocoupling of aryl sulfonates has been successfully achieved under mild conditions. This transformation is a new method for the homocoupling reaction of aryl sulfonates at room temperature via the cleavage of C─O bonds, thus providing an alternative synthesis of symmetric biaryls. The reported reductive homocoupling reaction is tolerant of many common functional groups regardless of electron-donating or electron-withdrawing nature, making this newly developed transformation important for complementing Ullmann coupling. Experimental Section. Typical procedure for the products.
- Zhong, Shuangling,Chen, Mengxin,Liu, Ge,Sun, Chenggang,Liu, Wencong
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- Feedstocks to Pharmacophores: Cu-Catalyzed Oxidative Arylation of Inexpensive Alkylarenes Enabling Direct Access to Diarylalkanes
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A Cu-catalyzed method has been identified for selective oxidative arylation of benzylic C-H bonds with arylboronic esters. The resulting 1,1-diarylalkanes are accessed directly from inexpensive alkylarenes containing primary and secondary benzylic C-H bonds, such as toluene or ethylbenzene. All catalyst components are commercially available at low cost, and the arylboronic esters are either commercially available or easily accessible from the commercially available boronic acids. The potential utility of these methods in medicinal chemistry applications is highlighted.
- Vasilopoulos, Aristidis,Zultanski, Susan L.,Stahl, Shannon S.
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p. 7705 - 7708
(2017/06/20)
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