- Rhodium-catalyzed coupling reaction of aroyl chlorides with alkenes
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Aroyl chlorides react with acyclic and cyclic alkenes in the presence of a rhodium catalyst to give Mizoroki-Heck type and cyclization products, respectively. A rhodium-ethylene complex, [{RhCl(C2H 4)2}2], showed excellent performance for these reactions. Notably, the reactions can be conducted effectively under base- and phosphane-free conditions.
- Sugihara, Toru,Satoh, Tetsuya,Miura, Masahiro,Nomura, Masakatsu
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- Silica-supported poly-γ-mercaptopropylsiloxane palladium(0) complex: A highly active and stereoselective catalyst for arylation of styrene and acrylic acid
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A silica-supported poly-γ-mercaptopropylsiloxane palladium(0) complex was prepared from poly-γ-mercaptopropylsiloxane and palladium chloride in acetone, followed by reduction with hydrazine in ethanol. The complex is a highly active and stereoselective catalyst for arylation of styrene and acrylic acid affording a variety of trans-stilbenes and substituted trans- cinnamic acids in high yields.
- Cai, Ming-Zhong,Song, Cai-Sheng,Huang, Xian
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- Catalytic activity of Pd dithiolate complexes with large-bite-angle diphosphines in Heck coupling reactions
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Palladium(II) complexes of aryl dithiolates and wide-bite-angle diphosphines Xantphos and dppf have been developed as efficient catalysts in Suzuki and Suzuki carbonylation reactions. The catalytic activity of these highly stable, discrete and charged complexes was investigated in Heck coupling reactions of styrene and a variety of aryl bromides. Under optimized reaction conditions these palladium complexes showed excellent activity with high turnover number (6 × 106) and high turnover frequency (4 × 105 h?1). The effect of bite angle of diphosphines on the catalytic activity of the complexes [Pd2(P∩P)2(SC12H8S)]2(OTf)4 followed the trend P∩P = Xantphos > dppf > dppe as the order of their bite angles. The catalyst could be reused, and after three cycles the formation of significant amount of Pd nanoparticles was noticed, which were characterized using powder X-ray diffraction, energy-dispersive X-ray analysis and transmission electron microscopy. The high catalytic activity has been attributed to the Pd nanoparticles.
- Mane, Pravin A.,Neogy, Suman,Dey, Sandip
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- Palladium-catalyzed carbon- carbon bond formation on a solid phase utilizing hypervalent iodonium salts
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Palladium-catalyzed cross-coupling of hypervalent iodonium salts with polymer bound alkene, alkyne, and boronate was achieved under mild conditions.
- Kang, Suk-Ku,Yoon, Seok-Keun,Lim, Kwon-Ho,Son, Hoe-Joo,Baik, Tae-Gon
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- Air-Driven Potassium Iodide-Mediated Oxidative Photocyclization of Stilbene Derivatives
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A new method has been developed for the potassium iodide-mediated oxidative photocyclization of stilbene derivatives. Compared with conventional iodine-mediated oxidative photocyclization reactions, this new method requires shorter reaction times and affords cyclized products in yields of 45-97%. This reaction proceeds with a catalytic amount of potassium iodide and works in an air-driven manner without the addition of an external scavenger. The radical-mediated oxidative photocyclization of stilbene derivatives using TEMPO was also investigated.
- Matsushima, Tomoya,Kobayashi, Sayaka,Watanabe, Soichiro
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- Cross-Coupling Catalysis by an Anionic Palladium Complex
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Recent studies have shown that anionic palladium complexes are viable catalysts for a range of catalytic cross-coupling reactions. We present a one-step synthesis of the anionic "ligandless" palladium complex [NBu4][Pd(DMSO)Cl3] together with its crystal structure. This compound has been shown to be an active precatalyst in the Mizoroki-Heck reaction. Under Jeffery conditions, activated aryl chlorides can be coupled in yields of up to 94% without the need of an additional ligand. The presence of a small amount of water was necessary for product formation. An Amatore-Jutand-type catalytic cycle is consistent with the results presented herein. For comparison with the known mixed complex [(pym-Im-Me)2PdCl][Pd(DMSO)Cl3], the cationic complex [(pym-Im-Me)2PdCl]PF6 (pym = pyrimidyl, Im = imidazolin-2-ylidene) has been synthesized and characterized using standard techniques.
- Schroeter, Felix,Soellner, Johannes,Strassner, Thomas
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- Silica-supported bidentate arsine palladium(0) complex: A highly active and stereoselective catalyst for arylation of conjugated alkenes
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A silica-supported bidentate arsine palladium(0) complex has been prepared from 4-oxa-6,7-dichloroheptyltriethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylarsenide and palladium chloride, and then the reduction with hydrazine hydrate. The complex has been characterized by X-ray photoelectron spectroscopy and it is a highly active and stereoselective catalyst for arylation of styrene and acrylic acid with aryl halides affording a variety of trans -stilbenes and substituted trans -cinnamic acids in high yields.
- Cai, Mingzhong,Huang, Yizheng,Zhao, Hong,Song, Caisheng
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- Heck reaction using palladium complexed to dendrimers on silica
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Polyamidoamine dendrimers, constructed on the surface of silica, were phosphonated using diphenylphosphinomethanol (prepared in situ) and complexed to form a palladium-dimethyl TMEDA complex. This catalyst was found to be effective in the Hack reaction of aryl bromides with both butyl acrylate and styrene, affording coupling products in moderate to good yields. The heterogeneous palladium catalyst can also be recycled and reused with only moderate reduction in activity.
- Alper,Arya,Bourque,Jefferson,Manzer
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- Macrocyclic Pd(II) dithiolate complexes as catalysts in Heck reactions
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The supramolecular palladium dithiolate complexes, [Pd2(dppe)2{S(C6H4)nS}]2(OTf)4and [Pd2(dppe)2(SCH2C6H4CH2S)]
- Mane, Pravin A.,Dey, Sandip,Vivekananda
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- Chemoselective and Sequential Palladium-Catalyzed Couplings for the Generation of Stilbene Libraries via Immobilized Substrates
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A versatile palladium-catalyzed tandem synthetic sequence to afford E-stilbenes libraries has been developed. Excellent regio- and stereocontrol have been achieved by means of the sequence of Hiyama and Heck cross-couplings. Undesirable homocoupling bypro
- Traficante, Carla I.,Fagundez, Catherine,Serra, Gloria L.,Mata, Ernesto G.,Delpiccolo, Carina M. L.
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- Ansa macrolides as molecular workbenches for stereoselective additions to achiral (E) olefins
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Highly stereocontrolled additions to achiral acyclic (E) olefins are achieved via incorporation into an ansa macrolide with a nonracemic stilbene diol (molecular workbench approach).
- Mulzer, Johann,Boehm, Ingo,Bats, Jan-W
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- Tandem Acceptorless Dehydrogenative Coupling-Decyanation under Nickel Catalysis
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The development of new catalytic processes based on abundantly available starting materials by cheap metals is always a fascinating task and marks an important transition in the chemical industry. Herein, a nickel-catalyzed acceptorless dehydrogenative coupling of alcohols with nitriles followed by decyanation of nitriles to access diversely substituted olefins is reported. This unprecedented C=C bond-forming methodology takes place in a tandem manner with the formation of formamide as a sole byproduct. The significant advantages of this strategy are the low-cost nickel catalyst, good functional group compatibility (ether, thioether, halo, cyano, ester, amino, N/O/S heterocycles; 43 examples), synthetic convenience, and high reaction selectivity and efficiency.
- Babu, Reshma,Balaraman, Ekambaram,Midya, Siba P.,Subaramanian, Murugan,Yadav, Vinita
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p. 7552 - 7562
(2021/06/28)
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- Highly selective electroreductive linear dimerization of electron-deficient vinylarenes
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A direct electroreductive dimerization of electron-deficient vinylarenes for the synthesis of 1,4-diarylbutane has been developed using a simple undivided cell with inexpensive carbon electrodes at room temperature. The control and deuterium-labeling experiments of electroreductive dimerization suggest that the hydrogen source comes from the solvent CH3CN. This protocol provides a mild and efficient route for the construction of C–C bond in moderate to good yields with high regioselectivity and broad substrate scope.
- Ning, Shulin,Zheng, Lianyou,Bai, Ya,Wang, Shutao,Wang, Siyu,Shi, Lingling,Gao, Qiansong,Che, Xin,Zhang, Zhuoqi,Xiang, Jinbao
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supporting information
(2021/11/16)
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- Ruthenium-Catalyzed E-Selective Partial Hydrogenation of Alkynes under Transfer-Hydrogenation Conditions using Paraformaldehyde as Hydrogen Source
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E-alkenes were synthesized with up to 100 % E/Z selectivity via ruthenium-catalyzed partial hydrogenation of different aliphatic and aromatic alkynes under transfer-hydrogenation conditions. Paraformaldehyde as a safe, cheap and easily available solid hydrogen carrier was used for the first time as hydrogen source in the presence of water for transfer-hydrogenation of alkynes. Optimization reactions showed the best results for the commercially available binuclear [Ru(p-cymene)Cl2]2 complex as pre-catalyst in combination with 2,2-bis(diphenylphosphino)-1,1-binaphthyl (BINAP) as ligand (1 : 1 ratio per Ru monomer to ligand). Mechanistic investigations showed that the origin of E-selectivity in this reaction is the fast Z to E isomerization of the formed alkenes. Mild reaction conditions plus the use of cheap, easily available and safe materials as well as simple setup and inexpensive catalyst turn this protocol into a feasible and promising stereo complementary procedure to the well-known Z-selective Lindlar reduction in late-stage syntheses. This procedure can also be used for the production of deuterated alkenes simply using d2-paraformaldehyde and D2O mixtures.
- Fetzer, Marcus N. A.,Tavakoli, Ghazal,Klein, Axel,Prechtl, Martin H. G.
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p. 1317 - 1325
(2021/02/11)
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- Palladium Nanoparticles Anchored on Magnesium Organosilicate: An Effective and Selective Catalyst for the Heck Reaction
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A new and effective palladium catalyst supported on a magnesium organosilicate for application in the Heck reaction is presented. A group of compounds comprising 22 examples were synthesized in moderate to high yields (up to 99%) within a short time. The palladium supported on magnesium organosilicate catalyst was characterized as an amorphous solid by SEM, containing around 33% of palladium inside the solid, and even with this low quantity of palladium, the catalyst was very efficient in the Heck reaction. Besides, based on the Scherrer equation, the crystallite size of the synthesized palladium nanoparticles was ultrasmall (around 1.3 nm). This strategy is a simple and efficient route for the formation of C-C bonds via the Heck cross-coupling reaction.
- Dos Santos, Beatriz F.,Da Silva, Beatriz A. L.,De Oliveira, Aline R.,Sarragiotto, Maria H.,Rinaldi, Andrelson W.,Domingues, Nelson Luís C.
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supporting information
p. 1301 - 1306
(2020/11/04)
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- N-Heterocyclic carbene palladium (II)-pyridine (NHC-Pd (II)-Py) complex catalyzed heck reactions
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A mild, efficient, and practical catalytic system for the synthesis of highly privileged stilbene pharmacophores is reported. This system uses N-heterocyclic carbene palladium (II) Pyridine (NHC-Pd (II)-Py) complex to catalyze the formation of carbon-carbon bonds between olefin derivatives and various bromide. This simple, gentle and user-friendly method can offer a variety of stilbene products in excellent yields under solvent-free condition. And its scale-up reaction has excellent yield and this system can be applied to industrial fields. The utility of this method is highlighted by its universality and modular synthesis of a series of bioactive molecules or important medical intermediates.
- Li, Dan,Tian, Qingqiang,Wang, Xuetong,Wang, Qiang,Wang, Yin,Liao, Siwei,Xu, Ping,Huang, Xin,Yuan, Jianyong
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supporting information
p. 2041 - 2052
(2021/05/25)
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- A Simple Nickel Catalyst Enabling an E-Selective Alkyne Semihydrogenation
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Stereoselective alkyne semihydrogenations are attractive approaches to alkenes, which are key building blocks for synthesis. With regards to the most atom-economic reducing agent dihydrogen (H2), only few catalysts for the challenging E-selective alkyne semihydrogenation have been disclosed, each with a unique substrate scope profile. Here, we show that a commercially available nickel catalyst facilitates the E-selective alkyne semihydrogenation of a wide variety of substituted internal alkynes. This results in a simple and broadly applicable overall protocol to stereoselectively access E-alkenes employing H2, which could serve as a general method for synthesis.
- Thiel, Niklas O.,Kaewmee, Benyapa,Tran Ngoc, Trung,Teichert, Johannes F.
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p. 1597 - 1603
(2020/02/05)
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- cis-Selective Transfer Semihydrogenation of Alkynes by Merging Visible-Light Catalysis with Cobalt Catalysis
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Herein, the first example of visible-light-driven, cobalt-catalyzed transfer semihydrogenation of alkynes to alkenes is reported. It is carried out by using Ir[dF(CF3)ppy]2(dtbbpy)]PF6 as photosensitizer, CoBr2/n-Bu3P as proton-reducing catalyst, and i-Pr2NEt/AcOH as the hydrogen source. Under the established catalytic system, the semihydrogenation proceeds with Z as the major selectivity and with inhibition of over-reduction. Under mild reaction conditions, both internal and terminal alkynes, as well as reducible functional groups such as halogen, cyano, and ester, are tolerated. Preliminary mechanistic studies revealed the dual role of the photosensitizer in initiating the reaction via a single-electron transfer process and controlling the stereoselectivity via an energy transfer process. (Figure presented.).
- Ding, Hai-Xin,Guo, Wen-Jie,He, Yong-Qin,Song, Xian-Rong,Tian, Wan-Fa,Xiao, Qiang,Ye, Jing
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supporting information
(2020/02/05)
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- Method for catalytically reducing alkynes into olefins through visible light induction
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The invention discloses a method for catalytically reducing alkynes into olefins through visible light induction. The method can avoid generation of over-reduced alkane products and the highest yieldis 99%. The method comprises the following steps: by taking an alkyne as a raw material, adding a photosensitizer and a cobalt catalyst, then adding a phosphine ligand or bipyridine ligand, an electronic sacrificial reagent, acetic acid and an organic solvent under inert gas protection, and irradiating with blue light at room temperature for 7-14 hours; and after the reaction is finished, spin-drying an obtained reaction solution, and carrying out silica gel column chromatography separation to obtain an olefin product; wherein the organic solvent is 1, 4-dioxane or tetrahydrofuran, and the alkyne is an aliphatic alkyne or an aromatic alkyne. Reduction of alkyne is realized through a hydrogen transfer strategy, use of dangerous hydrogen is avoided, generation of overreduction products is avoided, reaction conditions are mild, the reaction yield is high, and the method has a good application prospect.
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Paragraph 0039-0042
(2020/03/09)
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- Stereoselective Chromium-Catalyzed Semi-Hydrogenation of Alkynes
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Chromium complexes have found very little applications as hydrogenation catalysts. Here, we report a Cr-catalyzed semi-hydrogenation of internal alkynes to the corresponding Z-alkenes with good stereocontrol (up to 99/1 for dialkyl alkynes). The catalyst comprises the commercial reagents chromium(III) acetylacetonate, Cr(acac)3, and diisobutylaluminium hydride, DIBAL?H, in THF. The semi-hydrogenation operates at mild conditions (1-5 bar H2, 30 °C).
- Gregori, Bernhard J.,Nowakowski, Michal,Schoch, Anke,P?llath, Simon,Zweck, Josef,Bauer, Matthias,Jacobi von Wangelin, Axel
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p. 5359 - 5363
(2020/09/03)
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- An Annelated Mesoionic Carbene (MIC) Based Ru(II) Catalyst for Chemo- And Stereoselective Semihydrogenation of Internal and Terminal Alkynes
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The catalytic utility of [RuL1(CO)2I2] (1), containing an annelated π-conjugated imidazo-naphthyridine-based mesoionic carbene (MIC) ligand (L1), is evaluated for E-selective alkyne semihydrogenation. The precatalyst 1, in combination with 2 equiv of AgBArF, semihydrogenates a broad range of internal alkynes with molecular hydrogen (5 bar) in water. (E)-Alkenes are accessed in high yields, and a number of reducible functional groups are tolerated. A chelate MIC ligand and two cis carbonyls provide a well-defined platform at the Ru center for hydrogenation and isomerization. The loss of two iodides and the presence of two carbonyls render the Ru center electron deficient and thus the formation of metal vinylidenes with terminal alkynes is avoided. This is leveraged for the semihydrogenation of terminal alkynes by the same catalytic system in isopropyl alcohol. Reaction profile, isomerization, kinetic, and DFT studies reveal initial alkyne hydrogenation to a (Z)-alkene, which further isomerizes to an (E)-alkene via metal-catalyzed Z → E isomerization.
- Bera, Jitendra K.,Choudhury, Joyanta,Das, Shubhajit,Dutta, Indranil,Pati, Swapan K.,Saha, Sayantani,Yadav, Suman
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p. 3212 - 3223
(2020/10/02)
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- A photoredox catalysed Heck reaction: Via hole transfer from a Ru(ii)-bis(terpyridine) complex to graphene oxide
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The attachment of homoleptic Ru bis-terpy complexes on graphene oxide significantly improved the photocatalytic activity of the complexes. These straightforward complexes were applied as photocatalysts in a Heck reaction. Due to covalent functionalization on graphene oxide, which functions as an electron reservoir, excellent yields were obtained. DFT investigations of the charge redistribution revealed efficient hole transfer from the excited Ru unit towards the graphene oxide. This journal is
- Rosenthal, Marta,Lindner, J?rg K. N.,Gerstmann, Uwe,Meier, Armin,Schmidt, W. Gero,Wilhelm, René
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p. 42930 - 42937
(2020/12/18)
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- Palladium-Catalyzed Mizoroki-Heck Reaction of Nitroarenes and Styrene Derivatives
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We have developed a Mizoroki-Heck reaction of nitroarenes with alkenes under palladium catalysis. The use of a Pd/BrettPhos catalyst promoted the alkenylation, whereas other catalysts led to a decrease in the product yield. In addition to nitroarenes, nitroheteroarenes were also applicable to the present reaction. The combination of a nucleophilic aromatic substitution (SNAr) with the denitrative alkenylation produced a multifunctionalized arene in a one-pot operation.
- Okita, Toshimasa,Asahara, Kitty K.,Muto, Kei,Yamaguchi, Junichiro
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supporting information
p. 3205 - 3208
(2020/04/10)
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- Cobalt catalyzed stereodivergent semi-hydrogenation of alkynes using H2O as the hydrogen source
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Cobalt-catalyzed stereodivergent semi-hydrogenation of internal alkynes to alkenes is developed. The reaction proceeded through transfer hydrogenation under mild conditions using a base metal CoI2 as the catalyst, and H2O/MeOH as the hydrogen source with Zn as the reductant. The E/Z-selectivity of the product could be switched by changing the solvent and by inclusion/exclusion of a bidentate phosphine ligand (dppe). This method provides a simple and cost effective pathway for the synthesis of 1,2-dideuterioalkenes.
- Li, Kangkui,Khan, Ruhima,Zhang, Xuexin,Gao, Yang,Zhou, Yongyun,Tan, Heng,Chen, Jingchao,Fan, Baomin
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p. 5663 - 5666
(2019/05/21)
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- Stereoselective Alkyne Hydrogenation by using a Simple Iron Catalyst
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The stereoselective hydrogenation of alkynes constitutes one of the key approaches for the construction of stereodefined alkenes. The majority of conventional methods utilize noble and toxic metal catalysts. This study concerns a simple catalyst comprised of the commercial chemicals iron(II) acetylacetonate and diisobutylaluminum hydride, which enables the Z-selective semihydrogenation of alkynes under near ambient conditions (1–3 bar H2, 30 °C, 5 mol % [Fe]). Neither an elaborate catalyst preparation nor addition of ligands is required. Mechanistic studies (kinetic poisoning, X-ray absorption spectroscopy, TEM) strongly indicate the operation of small iron clusters and particle catalysts.
- Gregori, Bernhard J.,Schwarzhuber, Felix,P?llath, Simon,Zweck, Josef,Fritsch, Lorena,Schoch, Roland,Bauer, Matthias,Jacobi von Wangelin, Axel
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p. 3864 - 3870
(2019/07/31)
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- Magnetically thiamine palladium complex nanocomposites as an effective recyclable catalyst for facile sonochemical cross coupling reaction
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The carbon–carbon cross coupling reactions through transition-metal-catalyzed processes has been significantly developed for their important synthetic applications. In this research, we have shown that NiFe2O4@TASDA-Pd(0) is a highly active, novel and reusable catalyst with excellent performance for the Mizoroki–Heck coupling reaction of several types of iodo, bromo, and even aryl chlorides in DMF under ultrasound irradiation. The novel palladium catalyst prepared and characterized by using FT-IR spectrum, X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), thermo gravimetric analysis (TGA) and vibrating sample magnetometer (VSM). The catalyst can be recovered and recycled several times without marked loss of activity.
- Naeimi, Hossein,Kiani, Fatemeh
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- Catalytic Chemoselective and Stereoselective Semihydrogenation of Alkynes to E-Alkenes Using the Combination of Pd Catalyst and ZnI2
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An efficient E-selective semihydrogenation of internal alkynes was developed under low dihydrogen pressure and low reaction temperature from commercially available reagents: Cl2Pd(PPh3)2, Zn0, and ZnI2. Kinetic studies and control experiments underline the significant role of ZnI2 in this process under H2 atmosphere, establishing that the transformation involves syn-hydrogenation followed by isomerization. This simple and easy-to-handle system provides a route to E-alkenes under mild conditions.
- Maazaoui, Radhouan,Abderrahim, Raoudha,Chemla, Fabrice,Ferreira, Franck,Perez-Luna, Alejandro,Jackowski, Olivier
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supporting information
p. 7544 - 7549
(2019/01/03)
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- Stereodivergent Alkyne Reduction by using Water as the Hydrogen Source
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A homogeneous Pd-catalyzed stereodivergent reduction of alkynes to Z and E alkenes by using H2O as the H2 source is presented. Mediated by a diboron reagent, the transfer hydrogenation has been accomplished to yield the desired geometrical isomer by rational ligand selection. The switchable stereoselectivity achieved using simple phosphine ligands is generally excellent. D2O has also been used as a D2 source for synthesizing the corresponding deuterated olefins. Supported by a gram-scale synthesis, the reaction can easily be scaled up making it an efficient way to prepare alkenes commercially as well. Mechanistic studies suggest formation of H?PdL2?OAc as the crucial step leading to the presence of two pathways involving H?Pd?B(OR)2 and molecular H2 as active intermediates.
- Rao, Santhosh,Prabhu, Kandikere Ramaiah
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supporting information
p. 13954 - 13962
(2018/09/14)
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- Decarboxylative Arylation of α,β-Unsaturated Carboxylic Acids Using Aryl Triazenes by Copper/Ionic Liquid Combination in PEG-400
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A practical method for the construction of stilbene derivatives has been developed via catalytic cross-coupling of cinnamic acids with aryl triazenes. The methodology offers high stereoselectivity and is endowed with broad substrate scope, high yield, and significant functional group tolerance.
- Kumar, Saurabh,Kumar Pandey, Anand,Singh, Rahul,Nand Singh, Krishna
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supporting information
p. 5942 - 5946
(2018/11/10)
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- Group 4 Metallocene Difluoride/Palladium Bimetallic Catalysts for the Reductive Cross-Coupling of Alkynes with Aryl Iodides and Bromides
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A novel protocol has been developed for the selective synthesis of (E)-alkenes via the reductive cross-coupling of alkynes and aryl halides using a bimetallic catalyst system composed of a group 4 metallocene difluoride (Cp2[M]F2; [M] = Hf or Zr; Cp = cyclopentadienide) and palladium dichloride. This reaction proceeds via a coupling between an aryl halide and an in situ generated alkenyl metallocene intermediate derived from the group 4 metallocene difluoride, a hydrosilane, and an alkyne. For a catalytic reductive coupling, the addition of sodium fluoride (NaF) to the reaction system is required. Moreover, in the presence of NaF, a ligand exchange was observed by NMR spectroscopy in hafnocene diiodide (Cp2HfI2) to afford hafnocene difluoride (Cp2HfF2).
- Takahashi, Keita,Morishita, Hiromitsu,Ogiwara, Yohei,Sakai, Norio
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p. 13734 - 13742
(2018/11/03)
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- Discovery of highly selective and potent monoamine oxidase B inhibitors: Contribution of additional phenyl rings introduced into?2-aryl-1,3,4-oxadiazin-5(6H)-one
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Monoamine oxidase B (MAO-B) is a flavin adenine dinucleotide (FAD)-containing enzyme that plays a major role in the oxidative deamination of biogenic amines and neurotransmitters. Inhibiting MAO-B activity is a promising approach in the treatment of neuro
- Lee, Jungeun,Lee, Yeongcheol,Park, So Jung,Lee, Joohee,Kim, Yeong Shik,Suh, Young-Ger,Lee, Jeeyeon
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p. 365 - 378
(2017/03/10)
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- Preparation of Vinyl Arenes by Nickel-Catalyzed Reductive Coupling of Aryl Halides with Vinyl Bromides
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This work emphasizes the synthesis of substituted vinyl arenes by reductive coupling of aryl halides with vinyl bromides under mild and easy-to-operate nickel-catalyzed reaction conditions. A broad range of aryl halides, including heteroaromatics, and vinyl bromides were employed to yielding products in moderate to excellent yields with high functional-group tolerance. The nickel-catalytic system displays good chemoselectivity between the two C(sp2)-halide coupling partners, thus demonstrating a mechanistic pathway distinct from other stepwise protocols.
- Liu, Jiandong,Ren, Qinghua,Zhang, Xinghua,Gong, Hegui
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p. 15544 - 15548
(2016/12/09)
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- Ligand-Controlled Cobalt-Catalyzed Transfer Hydrogenation of Alkynes: Stereodivergent Synthesis of Z- and E-Alkenes
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Herein, we report a novel cobalt-catalyzed stereodivergent transfer hydrogenation of alkynes to Z- and E-alkenes. Effective selectivity control is achieved based on a rational catalyst design. Moreover, this mild system allows for the transfer hydrogenation of alkynes bearing a wide range of functional groups in good yields using catalyst loadings as low as 0.2 mol %. The general applicability of this procedure is highlighted by the synthesis of more than 50 alkenes with good chemo- and stereoselectivity. A preliminary mechanistic study revealed that E-alkene product was generated via sequential alkyne hydrogenation to give Z-alkene intermediate, followed by a Z to E alkene isomerization process.
- Fu, Shaomin,Chen, Nan-Yu,Liu, Xufang,Shao, Zhihui,Luo, Shu-Ping,Liu, Qiang
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p. 8588 - 8594
(2016/07/27)
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- Matsuda-Heck reaction with arenediazonium tosylates in water
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An environmentally friendly Matsuda-Heck reaction with arenediazonium tosylates has been developed for the first time. A range of alkenes was arylated in good to quantitative yields in water. The reaction is significantly accelerated when carried out under microwave heating. The arylation of haloalkylacrylates with diazonium salts has been implemented for the first time.
- Kutonova, Ksenia V.,Trusova, Marina E.,Stankevich, Andrey V.,Postnikov, Pavel S.,Filimonov, Victor D.
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supporting information
p. 358 - 362
(2015/06/16)
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- General Olefin Synthesis by the Palladium-Catalyzed Heck Reaction of Amides: Sterically Controlled Chemoselective N-C Activation
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Metal-catalyzed reactions of amides proceeding via metal insertion into the N-CO bond are severely underdeveloped due to resonance stabilization of the amide bond. Herein we report the first Heck reaction of amides proceeding via highly chemoselective N-CO cleavage catalyzed by Pd0 utilizing amide bond ground-state destabilization. Conceptually, this transformation provides access to a myriad of metal-catalyzed transformations of amides via metal insertion/decarbonylation.
- Meng, Guangrong,Szostak, Michal
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supporting information
p. 14518 - 14522
(2016/01/25)
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- Rhodium-catalyzed oxidative decarbonylative Heck-type coupling of aromatic aldehydes with terminal alkenes
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A rhodium-catalyzed oxidative decarbonylative Heck-type coupling of aromatic aldehydes with terminal alkenes to afford 1,2-disubstituted alkenes with good regio- and E-selectivity is developed. This reaction employs readily available aromatic aldehydes as the aryl electrophile counterpart and relies on selected acyl chloride as the crucial additive to activate the rhodium catalyst precursor.
- Kang, Lei,Zhang, Feng,Ding, Lin-Ting,Yang, Luo
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p. 100452 - 100456
(2015/12/09)
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- Ligand Control of E/Z Selectivity in Nickel-Catalyzed Transfer Hydrogenative Alkyne Semireduction
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A nickel-catalyzed transfer hydrogenative alkyne semireduction protocol that can be applied to both internal and terminal alkynes using formic acid and Zn as the terminal reductants has been developed. In the case of internal alkynes, the (E)- or (Z)-olefin isomer can be accessed selectively under the same reaction conditions by judicious inclusion of a triphos ligand.
- Richmond, Edward,Moran, Joseph
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p. 6922 - 6929
(2015/10/05)
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- Synthesis, characterization, and microwave-assisted catalytic activity in Heck, Suzuki, Sonogashira, and Buchwald-Hartwig cross-coupling reactions of novel benzimidazole salts bearing N-phthalimidoethyl and benzyl moieties
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Five novel benzimidazole salts (1-5) having N-phthalimidoethyl and 4-substituted benzyl were synthesized and identified by 1H NMR, 13C NMR, and IR spectroscopic methods and microanalysis. A mixture of the benzimidazole salts (1-5), Pd(OAc)2, and K2CO3 in DMF-H2O catalyzed, in high yield, the Suzuki-Miyaura and the Heck-Mizoroki cross-coupling reactions assisted by microwave irradiation in 5 min. The novel benzimidazole salts (1-5), Pd(OAc)2, Cs2CO3, PEG, and Cu nanoparticles catalyzed, in high yield, the Sonogashira coupling reaction promoted by microwave irradiation in 10 min. The same benzimidazole salts (1-5), Pd(OAc)2, Cs2CO3, and TBAB catalyzed, in moderate or low yield, the Buchwald-Hartwig reaction assisted by microwave irradiation in 60 min. The efficiency of the catalyst system in these four reactions was discussed as well as the electron-releasing and withdrawing substituent effects on the benzimidazole ligands.
- Kü?ükbay, Hasan,Yilmaz, ülkü,Yavuz, Kemal,Bu?day, Nesrin
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p. 1265 - 1278
(2016/03/01)
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- Stereospecific hydrodehalogenation of alkenyl bromides: A new approach to the synthesis of (E)-alkenes
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The pair NaBH4-TMEDA and catalytic PdCl2(PPh 3)2 in THF at room temperature is a mild and efficient system for the hydrodebromination of alkenyl bromides, providing a facile reduction procedure that allows completing the process advantageously, leading from aldehydes to (E)-alkenes. This journal is the Partner Organisations 2014.
- Chelucci, Giorgio
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supporting information
p. 4069 - 4072
(2014/04/03)
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- Evidences of release and catch mechanism in the Heck reaction catalyzed by palladium immobilized on highly cross-linked-supported imidazolium salts
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Palladium (10 wt%) on a highly cross-linked imidazolium-based material was used as catalyst in 0.1 mol% in the Heck reaction between several alkenes and aryl iodides. Products were obtained from good to high yields. Deeper investigations showed a release of Pd species in solution and their capture by the imidazolium-based support. When a sixfold amount of support was employed the re-captured Pd species (0.5-0.6 wt%) were not anymore catalytically active. This result represents a new interesting aspect of this work since the highly cross-linked imidazolium-based material can act also as Pd scavenger avoiding the release of the metal in solution. Important differences between Heck and Suzuki reactions have been evidenced when the reactions were carried out in the presence of the scavenging support.
- Pavia, Cinzia,Giacalone, Francesco,Bivona, Lucia Anna,Salvo, Anna Maria Pia,Petrucci, Chiara,Strappaveccia, Giacomo,Vaccaro, Luigi,Aprile, Carmela,Gruttadauria, Michelangelo
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- Efficient PEPPSI-themed palladium N-heterocyclic carbene precatalysts for the mizoroki-heck reaction
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Two sets of six PEPPSI (pyridine enhanced precatalyst preparation, stabilization, and initiation) themed palladium complexes of amide-functionalized N-heterocyclic carbenes [PdBr2(NHC)(Py)], where NHC = 1-acetamido-3-R-imidazolin-2-ylidene, 1-acetamido-3-R-benzimidazolin-2- ylidene and Py = pyridine, were prepared. Solid-state structures of all these complexes were determined by single-crystal X-ray diffraction methods. All complexes under scrutiny were found to adopt a trans arrangement with square-planar geometry. These complexes showed excellent catalytic activity toward the Mizoroki-Heck cross-coupling reaction of aryl chlorides and styrene. Benzimidazole-derived complexes exhibited better catalytic activity than imidazole-based complexes. Formation of palladium nanoparticles in the reaction mixture was evidenced by dynamic light scattering and transmission electron microscopy studies and a mercury poisoning experiment, suggesting the possible involvement of palladium nanoparticles in the catalytic reactions.
- Lin, Yong-Chieh,Hsueh, Hsin-Hsueh,Kanne, Shanker,Chang, Li-Kuang,Liu, Fu-Chen,Lin, Ivan J. B.,Lee, Gene-Hsiang,Peng, Shie-Ming
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p. 3859 - 3869
(2013/08/23)
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- A mild chemoselective Ru-catalyzed reduction of alkynes, ketones, and nitro compounds
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The chemoselective reduction of alkyne, ketones, or nitro groups using (Ph3P)3RuCl2 as an inexpensive catalyst and Zn/water as a stoichiometric reductant is reported. Depending on the nature of the additive and the temperature, good chemoselectivities were observed allowing, e.g., for the selective reduction of a nitro group in the presence of a ketone or an alkyne.
- Schabel, Tobias,Belger, Christian,Plietker, Bernd
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p. 2858 - 2861
(2013/07/19)
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- Part I: The development of the catalytic wittig reaction
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We have developed the first catalytic (in phosphane) Wittig reaction (CWR). The utilization of an organosilane was pivotal for success as it allowed for the chemoselective reduction of a phosphane oxide. Protocol optimization evaluated the phosphane oxide precatalyst structure, loading, organosilane, temperature, solvent, and base. These studies demonstrated that to maintain viable catalytic performance it was necessary to employ cyclic phosphane oxide precatalysts of type 1. Initial substrate studies utilized sodium carbonate as a base, and further experimentation identified N,N-diisopropylethylamine (DIPEA) as a soluble alternative. The use of DIPEA improved the ease of use, broadened the substrate scope, and decreased the precatalyst loading. The optimized protocols were compatible with alkyl, aryl, and heterocyclic (furyl, indolyl, pyridyl, pyrrolyl, and thienyl) aldehydes to produce both di- and trisubstituted olefins in moderate-to-high yields (60-96 %) by using a precatalyst loading of 4-10 mol %. Kinetic E/Z selectivity was generally 66:34; complete E selectivity for disubstituted α,β-unsaturated products was achieved through a phosphane-mediated isomerization event. The CWR was applied to the synthesis of 54, a known precursor to the anti-Alzheimer drug donepezil hydrochloride, on a multigram scale (12.2 g, 74 % yield). In addition, to our knowledge, the described CWR is the only transition-/heavy-metal-free catalytic olefination process, excluding proton-catalyzed elimination reactions. A point of difference: By utilizing an organosilane to chemoselectively reduce a phosphane oxide precatalyst to a phosphane (see scheme), the first catalytic (in phosphane) Wittig reaction has been developed. The methodology has been applied to the synthesis of 22 disubstituted and 24 trisubstituted olefins, including a multigram synthesis of a precursor to the anti-Alzheimer drug donepezil hydrochloride.
- O'Brien, Christopher J.,Nixon, Zachary S.,Holohan, Andrew J.,Kunkel, Stephen R.,Tellez, Jennifer L.,Doonan, Bryan J.,Coyle, Emma E.,Lavigne, Florie,Kang, Lauren J.,Przeworski, Katherine C.
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supporting information
p. 15281 - 15289
(2013/11/06)
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- Cobalt-catalyzed vinylation of aromatic halides using β-halostyrene: Experimental and DFT studies
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A new protocol for the direct cobalt-catalyzed vinylation of aryl halides using β-halostyrene has been developed in order to form functionalized stilbenes. A variety of aromatic halides featuring different reactive group were employed. This method proceeded smoothly with a total retention of the double bond configuration in the presence of triphenylphosphine as ligand. Preliminary DFT calculations rationnalize these results and proposed a reaction pathway in agreement with the experimental conditions. This procedure offers a new route to the stereoselective synthesis of stilbenes.
- Moncomble, Aurelien,Floch, Pascal Le,Lledos, Agusti,Gosmini, Corinne
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experimental part
p. 5056 - 5062
(2012/07/14)
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- Aryl-aryl interactions as directing motifs in the stereodivergent iron-catalyzed hydrosilylation of internal alkynes
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The defined Fe hydride complex FeH(CO)(NO)(Ph3P)2 is highly active as a catalyst for selective hydrosilylation of internal alkynes to vinylsilanes. Depending on the silane employed either E- or Z-selective hydrosilylation products were formed in excellent yields and good to excellent stereoselectivities.
- Belger, Christian,Plietker, Bernd
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p. 5419 - 5421
(2012/07/03)
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- Dehydrogenative heck reaction of furans and thiophenes with styrenes under mild conditions and influence of the oxidizing agent on the reaction rate
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CiH vs. CiBr in Heck: The direct dehydrogenative coupling of furans and thiophenes with styrenes occurs under mild conditions (see scheme). This method allows the coupling of brominated substrates through CiH bond activation. In addition, DMSO and benzoquinone had a positive effect on the reaction rate.
- Vasseur, Alexandre,Muzart, Jacques,Le Bras, Jean
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body text
p. 12556 - 12560
(2011/12/04)
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- CATALYTIC WITTIG AND MITSUNOBU REACTIONS
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A catalytic Wittig method utilizing a phosphine including the steps of providing a phosphine oxide precatalyst and reducing the phosphine oxide precatalyst to produce the phosphine; forming a phosphonium ylide precursor from the phosphine and a reactant; generating a phosphonium ylide from the phosphonium ylide precursor; reacting the phosphonium yiide precursor with the aldehyde, ketone, or ester to form the olefin and the phosphine oxide which then reenters the cycle. The invention is also directed to a Mitsunobu reaction catalytic in phosphine.
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Page/Page column 17
(2010/11/03)
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- Ultrasound-assisted synthesis of Z and E stilbenes by Suzuki cross-coupling reactions of organotellurides with potassium organotrifluoroborate salts
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Palladium (0)-catalyzed cross-coupling reactions between potassium aryl- and vinyltrifluoroborate salts and aryl- and vinylic tellurides proceeds readily to afford the desired stilbenes in good to excellent yields. Stilbenes containing a variety of functional groups can be prepared.
- Cella, Rodrigo,Stefani, Hélio A.
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p. 5656 - 5662
(2007/10/03)
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- Palladium Nanoparticles in Polymers: Catalyst for Alkene Hydrogenation, Carbon-Carbon Cross-Coupling Reactions, and Aerobic Alcohol Oxidation
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A new recyclable palladium catalyst was synthesized by a simple procedure from readily available reagents, which is composed of palladium nanoparticles dispersed in an organic polymer. This catalyst is robust, and highly active in many organic transformations including alkene and alkyne hydrogenation, carbon-carbon cross-coupling reactions, and aerobic alcohol oxidation.
- Park, Cheon Min,Kwon, Min Serk,Park, Jaiwook
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p. 3790 - 3794
(2008/02/09)
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- Synthesis, dual fluorescence, and fluoroionophoric behavior of dipyridylaminomethylstilbenes
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The synthesis, dual fluorescence, and fluoroionophoric behavior of two donor-σ spacer-acceptor (D-s-A) compounds, trans-4-(N,N-bis(2-pyridyl) amino)methylstilbene (1H) and trans-4-(N,N-bis(2-pyridyl)amino)methyl-4′- cyanostilbene (1CN), are reported and compared to that of trans-4-(N,N-bis(2- pyridyl)amino)methyl-4′-(N,N-dimethylammo)stilbene (1DPA). To gain insights into the dual fluorescence properties for 1H and 1CN in polar but not in nonpolar solvents, model compounds resulting from a replacement of the stilbene group by alkyl (2R) or xylyl (2X) groups or from a replacement of the dipyridylamino (dpa) group by dianisoleamino (3AA), diethylamino (SEE), methylanilino (3MP), or diphenylamino (3PP) groups also have been investigated. In addition to 1H and 1CN, all four compounds of 3 display dual fluorescence. The locally excited (LE) fluorescence mainly results from the stilbene group and the ICT fluorescence from the through-bond interactions between the amino donor and the stilbene acceptors. In the presence of transition metal ions such as Zn(II), Ni(II), Cu(II), and Cd(II), the ICT processes are switched from dpa → stilbene (A) in 1H and 1CN to stilbene (D) → dpa/metal ion (A) in their complexes. Whereas the ICT states for the complexes are generally nonfluorescent, an exception was found for the case of 1H/Zn(II). As a result, substituent-dependent fluoroionophoric behavior has been demonstrated by 1H, 1CN, and 1DPA in response to Zn(II).
- Yang, Jye-Shane,Lin, Yan-Duo,Chang, Ya-Ho,Wang, Shin-Shin
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p. 6066 - 6073
(2007/10/03)
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- Electrochemically assisted heck reactions
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(Chemical Equation Presented) During efforts to develop chip-based Heck reaction chemistry, it was discovered that normal solution-phase Heck reactions can be dramatically accelerated using electrochemistry. The acceleration makes room temperature Heck reactions proceed at synthetically useful rates in the absence of added ligand. Presumably, the current passed through the reaction maintains a high level of active catalyst.
- Tian, Jun,Moeller, Kevin D.
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p. 5381 - 5383
(2007/10/03)
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- 5′-Tethered Stilbene Derivatives as Fidelity- and Affinity-Enhancing Modulators of DNA Duplex Stability
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A series of 5′-linked stilbene-DNA conjugates with different substituents in the distal aromatic ring of the stilbene was prepared, and the effect of the modifications on duplex stability was determined via UV-melting curves. A trimethoxystilbene derivative as a 5′-substituent increases duplex melting points by up to 12.2 °C per modification. With this alkoxystilbene substituent, terminal mismatches in DNA duplexes lower the melting point by up to 23.4 °C over the perfectly matched control, whereas terminal mismatches in unmodified DNA cause melting point depressions of no more than 6.1 °C. An aminomethylstilbene substituent linked to an oligopyrrolamide minor groove binder increases the melting point of an all-A/T decamer by up to 32.7 °C, thus shifting the melting point into a range typical for duplexes with statistical G/C-content. An affinity- and selectivity-enhancing effect was also observed when the trimethoxystilbene cap was employed on a small DNA microarray. The phosphoramidite of the trimethoxystilbene can be readily employed in automatic DNA synthesis, facilitating the generation of DNA chips with improved fidelity. Copyright
- Dogan, Zeynep,Paulini, Ralph,Stuetz, Jan A. Rojas,Narayanan, Sukunath,Richert, Clemens
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p. 4762 - 4763
(2007/10/03)
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- A novel thiourea ligand applied in the Pd-catalyzed Heck, Suzuki and Suzuki carbonylative reactions
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A novel C2 symmetrical and sterically bulky thiourea ligand 1 has been successfully applied to Heck, Suzuki and Suzuki-type carbonylative coupling reactions under aerobic conditions. Since the metal-sulfur bond in the thiourea complexes is stronger than the metal-phosphorus bond of typical phosphine complexes, thiourea ligands generally do not easily dissociate from the metal center under catalytic conditions, which establishes the thiourea 1-based palladium complexes as effective catalysts for the palladium-catalyzed cross-coupling reactions.
- Mingji, Dai,Liang, Bo,Wang, Cuihua,You, Zejin,Xiang, Jing,Dong, Guangbin,Chen, Jiahua,Yang, Zhen
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p. 1669 - 1673
(2007/10/03)
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- One-pot synthesis of recyclable palladium catalysts for hydrogenations and carbon-carbon coupling reactions
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Palladium nanoparticles were generated from tetrakis(triphenylphophine) palladium in a mixture of tetra(ethylene glycol) and tetramethoxysilane (or titanium(IV) isopropoxide), then encapsulated in silica matrix (or titania matrix) by the treatment with water. The resulting heterogeneous material showed high catalytic activity in the hydrogenations of various alkene and alkynes and in the carbon-carbon cross-coupling reactions such as the Suzuki-Miyaura, the Sonogashira, the Heck-Mizoroki, and the Stille reactions.
- Kim, Namdu,Kwon, Min Serk,Park, Cheon Min,Park, Jaiwook
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p. 7057 - 7059
(2007/10/03)
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