- Metal-Organic Framework-Confined Single-Site Base-Metal Catalyst for Chemoselective Hydrodeoxygenation of Carbonyls and Alcohols
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Chemoselective deoxygenation of carbonyls and alcohols using hydrogen by heterogeneous base-metal catalysts is crucial for the sustainable production of fine chemicals and biofuels. We report an aluminum metal-organic framework (DUT-5) node support cobalt(II) hydride, which is a highly chemoselective and recyclable heterogeneous catalyst for deoxygenation of a range of aromatic and aliphatic ketones, aldehydes, and primary and secondary alcohols, including biomass-derived substrates under 1 bar H2. The single-site cobalt catalyst (DUT-5-CoH) was easily prepared by postsynthetic metalation of the secondary building units (SBUs) of DUT-5 with CoCl2 followed by the reaction of NaEt3BH. X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy (XANES) indicated the presence of CoII and AlIII centers in DUT-5-CoH and DUT-5-Co after catalysis. The coordination environment of the cobalt center of DUT-5-Co before and after catalysis was established by extended X-ray fine structure spectroscopy (EXAFS) and density functional theory. The kinetic and computational data suggest reversible carbonyl coordination to cobalt preceding the turnover-limiting step, which involves 1,2-insertion of the coordinated carbonyl into the cobalt-hydride bond. The unique coordination environment of the cobalt ion ligated by oxo-nodes within the porous framework and the rate independency on the pressure of H2 allow the deoxygenation reactions chemoselectively under ambient hydrogen pressure.
- Antil, Neha,Kumar, Ajay,Akhtar, Naved,Newar, Rajashree,Begum, Wahida,Manna, Kuntal
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supporting information
p. 9029 - 9039
(2021/06/28)
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- Palladium-Catalyzed Decarbonylative Iodination of Aryl Carboxylic Acids Enabled by Ligand-Assisted Halide Exchange
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We report an efficient and broadly applicable palladium-catalyzed iodination of inexpensive and abundant aryl and vinyl carboxylic acids via in situ activation to the acid chloride and formation of a phosphonium salt. The use of 1-iodobutane as iodide source in combination with a base and a deoxychlorinating reagent gives access to a wide range of aryl and vinyl iodides under Pd/Xantphos catalysis, including complex drug-like scaffolds. Stoichiometric experiments and kinetic analysis suggest a unique mechanism involving C?P reductive elimination to form the Xantphos phosphonium chloride, which subsequently initiates an unusual halogen exchange by outer sphere nucleophilic substitution.
- Boehm, Philip,Cacherat, Bastien,Lee, Yong Ho,Martini, Tristano,Morandi, Bill
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supporting information
p. 17211 - 17217
(2021/07/02)
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- Synthesis of biaryl compounds via Suzuki homocoupling reactions catalyzed by metal organic frameworks encapsulated with palladium nanoparticles
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Heterogeneous homocoupling reactions of phenylboronic acids were greatly accelerated via Suzuki homocoupling reactions. In this work, a tandem route was designed which firstly one part of phenylboronic acids reacted with iodine to form iodobenzenes, then another part of phenylboronic acids coupled with iodobenzenes to produce biaryl compounds. The tandem reaction were catalyzed by a bifunctional heterogeneous catalyst of metal organic frameworks encapsulated with palladium nanoparticles (Pd?MOFs). This strategy for forming symmetric C-C bond between benzene rings has obvious advantages such as high efficiency, easy separation, good recyclability and no addition of toxic halogenated benzene.
- Bao, Yan-Sai,Cui, Xin-Yu,Han, Zheng-Bo,Li, Xin,Tang, Hong,Yang, Ming,Zhang, Yu-Yang,Zhao, Kun,Zhou, Mei-Li
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- The graphite-catalyzed: ipso -functionalization of arylboronic acids in an aqueous medium: metal-free access to phenols, anilines, nitroarenes, and haloarenes
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An efficient, metal-free, and sustainable strategy has been described for the ipso-functionalization of phenylboronic acids using air as an oxidant in an aqueous medium. A range of carbon materials has been tested as carbocatalysts. To our surprise, graphite was found to be the best catalyst in terms of the turnover frequency. A broad range of valuable substituted aromatic compounds, i.e., phenols, anilines, nitroarenes, and haloarenes, has been prepared via the functionalization of the C-B bond into C-N, C-O, and many other C-X bonds. The vital role of the aromatic π-conjugation system of graphite in this protocol has been established and was observed via numerous analytic techniques. The heterogeneous nature of graphite facilitates the high recyclability of the carbocatalyst. This effective and easy system provides a multipurpose approach for the production of valuable substituted aromatic compounds without using any metals, ligands, bases, or harsh oxidants.
- Badgoti, Ranveer Singh,Dandia, Anshu,Parewa, Vijay,Rathore, Kuldeep S.,Saini, Pratibha,Sharma, Ruchi
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p. 18040 - 18049
(2021/05/29)
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- Generation of Organozinc Reagents from Arylsulfonium Salts Using a Nickel Catalyst and Zinc Dust
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Readily available aryldimethylsulfonium triflates react with zinc powder under nickel catalysis via the selective cleavage of the sp2-hybridized carbon-sulfur bond to produce salt-free arylzinc triflates under mild conditions. This zincation displays superb chemoselectivity and thus represents a protocol that is complementary or orthogonal to existing methods. The generated arylzinc reagents show both high reactivity and chemoselectivity in palladium-catalyzed and copper-mediated cross-coupling reactions.
- Yamada, Kodai,Yanagi, Tomoyuki,Yorimitsu, Hideki
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p. 9712 - 9718
(2021/01/09)
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- Orthogonal Stability and Reactivity of Aryl Germanes Enables Rapid and Selective (Multi)Halogenations
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While halogenation is of key importance in synthesis and radioimaging, the currently available repertoire is largely designed to introduce a single halogen per molecule. This report makes the selective introduction of several different halogens accessible. Showcased here is the privileged stability of nontoxic aryl germanes under harsh fluorination conditions (that allow selective fluorination in their presence), while displaying superior reactivity and functional-group tolerance in electrophilic iodinations and brominations, outcompeting silanes or boronic esters under rapid and additive-free conditions. Mechanistic experiments and computational studies suggest a concerted electrophilic aromatic substitution as the underlying mechanism.
- Deckers, Kristina,Fricke, Christoph,Schoenebeck, Franziska
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supporting information
p. 18717 - 18722
(2020/08/25)
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- Green synthesis method for p-iodotoluene
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The invention discloses a green synthesis method for p-iodotoluene, belonging to the technical field of synthesis of organic matters. According to the invention, perfluorosulfonic acid resin is adopted as a solid acid catalyst; due to a steric hindrance effect, the perfluorosulfonic acid resin mainly activates para-position hydrogen atoms of the p-iodotoluene; an oxidizing agent oxidizes iodine iniodized salt into iodine free radicals; the iodine free radicals attack the para-position activated hydrogen atoms of the p-iodotoluene; thus, a product, namely the p-iodotoluene is obtained. The green synthesis method provided by the invention has the following advantages: cheap and easily available toluene and iodized salt are used for respectively replacing expensive p-toluidine and periodic acid used in a conventional technology; meanwhile, reaction conditions are mild; after completion of the reaction, a solid catalyst, a carboxylic acid aqueous solution used as a reaction solvent and unreacted toluene can be recovered through centrifugation or filtration; the product, namely the p-iodotoluene is separated and recovered through a multi-stage extraction-flash evaporation-low-temperature crystallization process; and the green synthesis method provided by the invention has high yield, does not discharge three wastes in the preparation process, and is a green synthesis method.
- -
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Paragraph 0031-0040
(2020/04/17)
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- Arene diazonium saccharin intermediates: A greener and cost-effective alternative method for the preparation of aryl iodide
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In the current protocol, the arene diazonium saccharin derivatives were initially produced from various substituted aromatic amines; subsequently, these intermediates were treated with a greener organic iodide for the preparation of the aryl iodide. We tried to choose low-cost, commercially available, biodegradable, recoverable, ecofriendly, and safe reagents and solvents. The arene diazonium saccharin intermediates could be stored in the liquid phase into a refrigerator for a long time with no significant loss activity. The outstanding merits of the current protocol (a) included the partial recovering of saccharin and tetraethylammonium salt, (b) reduce the use of solvents and the reaction steps due to eliminating separation and purification of intermediates, (c) good yield of the sterically hindered substrates, and (d) avoid the generation of heavy metal or corrosive waste.
- Ghaffari Khaligh, Nader,Rafie Johan, Mohd,Shahnavaz, Zohreh,Zaharani, Lia
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p. 535 - 542
(2020/06/01)
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- Methane Generation and Reductive Debromination of Benzylic Position by Reconstituted Myoglobin Containing Nickel Tetradehydrocorrin as a Model of Methyl-coenzyme M Reductase
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Methyl-coenzyme M reductase (MCR), which contains the nickel hydrocorphinoid cofactor F430, is responsible for biological methane generation under anaerobic conditions via a reaction mechanism which has not been completely elucidated. In this work, myoglobin reconstituted with an artificial cofactor, nickel(I) tetradehydrocorrin (NiI(TDHC)), is used as a protein-based functional model for MCR. The reconstituted protein, rMb(NiI(TDHC)), is found to react with methyl donors such as methyl p-toluenesulfonate and trimethylsulfonium iodide with methane evolution observed in aqueous media containing dithionite. Moreover, rMb(NiI(TDHC)) is found to convert benzyl bromide derivatives to reductively debrominated products without homocoupling products. The reactivity increases in the order of primary > secondary > tertiary benzylic carbons, indicating steric effects on the reaction of the nickel center with the benzylic carbon in the initial step. In addition, Hammett plots using a series of para-substituted benzyl bromides exhibit enhancement of the reactivity with introduction of electron-withdrawing substituents, as shown by the positive slope against polar substituent constants. These results suggest a nucleophilic SN2-type reaction of the Ni(I) species with the benzylic carbon to provide an organonickel species as an intermediate. The reaction in D2O buffer at pD 7.0 causes a complete isotope shift of the product by +1 mass unit, supporting our proposal that protonation of the organonickel intermediate occurs during product formation. Although the turnover numbers are limited due to inactivation of the cofactor by side reactions, the present findings will contribute to elucidating the reaction mechanism of MCR-catalyzed methane generation from activated methyl sources and dehalogenation.
- Hayashi, Takashi,Miyazaki, Yuta,Oohora, Koji
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supporting information
p. 11995 - 12004
(2020/09/15)
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- Generation of Organozinc Reagents by Nickel Diazadiene Complex Catalyzed Zinc Insertion into Aryl Sulfonates
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The generation of arylzinc reagents (ArZnX) by direct insertion of zinc into the C?X bond of ArX electrophiles has typically been restricted to iodides and bromides. The insertions of zinc dust into the C?O bonds of various aryl sulfonates (tosylates, mesylates, triflates, sulfamates), or into the C?X bonds of other moderate electrophiles (X=Cl, SMe) are catalyzed by a simple NiCl2–1,4-diazadiene catalyst system, in which 1,4-diazadiene (DAD) stands for diacetyl diimines, phenanthroline, bipyridine and related ligands. Catalytic zincation in DMF or NMP solution at room temperature now provides arylzinc sulfonates, which undergo typical catalytic cross-coupling or electrophilic substitution reactions.
- Klein, Philippe,Lechner, Vivien Denise,Schimmel, Tanja,Hintermann, Lukas
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supporting information
p. 176 - 180
(2019/12/11)
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- Facile Access to Diverse Libraries of Internal Alkynes via Sequential Iododediazoniation/Decarboxylative Sonogashira Reaction in Imidazolium ILs without Ligand or Additive
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Convenient access to diverse libraries of internal alkynes via decarboxylative Sonogashira reaction of alkynyl-carboxylic acids with iodoarenes, employing imidazolium-ILs as solvent, along with piperidine-appended imidazolium [PAIM][NTf2] as task-specific basic IL is demonstrated, without the need for any ligand or additive. The feasibility to perform these reactions by sequential one-pot iododediazoniation/decarboxylative Sonogashira reaction is also shown, and the scope of the methods is underscored by providing 29 examples. The potential for recycling and reuse of the IL solvent is also examined.
- Prabhala, Pavankumar,Savanur, Hemantkumar M.,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
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supporting information
p. 2061 - 2064
(2019/03/07)
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- ipso-Bromination/iodination of arylboronic acids: Poly(4-vinylpyridine)-Br2/I2 complexes as safe and efficient reagents
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Poly(4-vinyl pyridine) supported bromine/iodine complexes were prepared and probed for ipso-bromination/iodination of arylboronic acids. These solid complexes with catalytic amount of additive are found to be safe and efficient reagent system for the ipso-bromination/iodination. The reaction occurs under mild conditions and tolerates various functional groups resulting in products with high selectivity and yields.
- Fu, Fang,Gurung, Laxman,Czaun, Miklos,Mathew, Thomas,Prakash, G.K. Surya
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supporting information
(2019/08/26)
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- Visible-Light-Induced Decarboxylative Iodination of Aromatic Carboxylic Acids
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A convenient, efficient and practical visible-light-induced decarboxylative iodination of aromatic carboxylic acids has been developed, and the corresponding aryl iodides were obtained in good yields. The method shows some advantages including the use of readily available aromatic carboxylic acids as the starting materials, simple and mild conditions, high efficiency, wide substrate scope and tolerance of various functional groups.
- Jiang, Min,Yang, Haijun,Jin, Yunhe,Ou, Lunyu,Fu, Hua
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supporting information
p. 1572 - 1577
(2018/06/26)
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- An efficient gram scale synthesis of aryl iodides from aryl diazofluoroborates in water under mild conditions
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Transition metal-free synthesis of synthetically valuable aryl iodides from aryl diazofluroborates in water under mild conditions has been described. Majority of synthesized aryl iodides are obtained in quantitative yields (>99%) under present reaction conditions. The structural effects due to the substituents present on aryl diazofluoroborates did not show any satisfactory effect on the yields of the aryl iodides. Hence, the methodology presented here was found to be adventitious for the quantitative production of synthetically valuable aryl iodides.
- Gholap, Somnath S.
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p. 594 - 599
(2018/06/26)
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- A general electrochemical strategy for the Sandmeyer reaction
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Herein we report a general electrochemical strategy for the Sandmeyer reaction. Using electricity as the driving force, this protocol employs a simple and inexpensive halogen source, such as NBS, CBrCl3, CH2I2, CCl4, LiCl and NaBr for the halogenation of aryl diazonium salts. In addition, we found that these electrochemical reactions could be performed using anilines as the starting material in a one-pot fashion. Furthermore, the practicality of this process was demonstrated in the multigram scale synthesis of aryl halides using highly inexpensive graphite as the electrode. A series of detailed mechanism studies have been performed, including radical clock and radical scavenger study, cyclic voltammetry analysis and in situ electron paramagnetic resonance (EPR) analysis.
- Liu, Qianyi,Sun, Beiqi,Liu, Zheng,Kao, Yi,Dong, Bo-Wei,Jiang, Shang-Da,Li, Feng,Liu, Guoquan,Yang, Yang,Mo, Fanyang
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p. 8731 - 8737
(2018/12/10)
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- Electrochemical Synthesis of Aryl Iodides by Anodic Iododesilylation
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An electrochemical access to iodinated aromatic compounds starting from trimethylsilyl-substituted arenes is presented. By design of experiments, highly efficient and mild conditions were identified for a wide range of substrates. A functional group stability test and the synthesis of an important 3-iodobenzylguanidine radiotracer illustrate the scope of this process.
- M?ckel, Robert,Hille, Jessica,Winterling, Erik,Weidemüller, Stephan,Faber, Tabea Melanie,Hilt, Gerhard
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supporting information
p. 442 - 445
(2018/02/21)
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- A simple and efficient iodination of aromatic compounds using I2/Choline Chloride/K2S2O8
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A simple and efficient method for the iodination of aromatic compounds has been achieved in the presence of molecular iodine, choline chloride and potassium peroxodisulfate at 65 °C in acetonitrile. The rate of conversion of aromatic compounds into iodoaromatic compounds was promoted by in situ formed choline peroxodisulfate. This protocol provides an efficient access to iodoarenes with operational simplicity, good functional group tolerance and a moderate to good product yield.
- Parthiban,Joel Karunakaran
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p. 1659 - 1663
(2018/06/12)
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- Metal-Free, Oxidant-Free, and Controllable Graphene Oxide Catalyzed Direct Iodination of Arenes and Ketones
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A direct, metal-free, and oxidant-free method for the graphene oxide (GO)-catalyzed iodination of arenes and ketones with iodine in a neutral medium was explored. This iodination protocol was performed by using a simple technique to avoid the use of external metal catalysts and oxidants and harsh acidic/basic reaction conditions. In addition, by this method the degree of iodination could be controlled, and the reaction was scalable and compatible with air. This strategy opens a new field for GO-catalyzed chemistry and provides an avenue for the convenient direct iodination of arenes and ketones.
- Zhang, Jingyu,Li, Shiguang,Deng, Guo-Jun,Gong, Hang
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p. 376 - 380
(2017/12/07)
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- Direct Pd(II)-Catalyzed Site-Selective C5-Arylation of 2-Pyridone Using Aryl Iodides
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A straightforward Pd(II)-catalyzed general strategy was developed for the C5-selective arylation of the 2-pyridone core with easily available aryl iodides. The transformation was highly regioselective and accomplished with a wide scope and functional group tolerance. Silver nitrate played a crucial role in this direct site-selective arylation. The method was extended to synthesize biologically active molecules.
- Maity, Saurabh,Das, Debapratim,Sarkar, Souradip,Samanta, Rajarshi
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supporting information
p. 5167 - 5171
(2018/09/13)
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- Metathesis-active ligands enable a catalytic functional group metathesis between aroyl chlorides and aryl iodides
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Current methods for functional group interconversion have, for the most part, relied on relatively strong driving forces which often require highly reactive reagents to generate irreversibly a desired product in high yield and selectivity. These approaches generally prevent the use of the same catalytic strategy to perform the reverse reaction. Here we describe a catalytic functional group metathesis approach to interconvert, under CO-free conditions, two synthetically important classes of electrophiles that are often employed in the preparation of pharmaceuticals and agrochemicals—aroyl chlorides (ArCOCl) and aryl iodides (ArI). Our reaction design relies on the implementation of a key reversible ligand C–P bond cleavage event, which enables a non-innocent, metathesis-active phosphine ligand to mediate a rapid aryl group transfer between the two different electrophiles. Beyond enabling a practical and safer approach to the interconversion of ArCOCl and ArI, this type of ligand non-innocence provides a blueprint for the development of a broad range of functional group metathesis reactions employing synthetically relevant aryl electrophiles.
- Lee, Yong Ho,Morandi, Bill
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p. 1016 - 1022
(2018/09/06)
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- Functional Group Transposition: A Palladium-Catalyzed Metathesis of Ar-X σ-Bonds and Acid Chloride Synthesis
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We describe the development of a new method to use palladium catalysis to form functionalized aromatics: via the metathesis of covalent σ-bonds between Ar-X fragments. This transformation demonstrates the dynamic nature of palladium-based oxidative addition/reductive elimination and offers a straightforward approach to incorporate reactive functional groups into aryl halides through exchange reactions. The reaction has been exploited to assemble acid chlorides without the use of high energy halogenating or toxic reagents and, instead, via the metathesis of aryl iodides with other acid chlorides.
- De La Higuera Macias, Maximiliano,Arndtsen, Bruce A.
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supporting information
p. 10140 - 10144
(2018/08/23)
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- A facile and sustainable protocol to the preparation of aryl iodides using stable arenediazonium bis(trifluoromethylsulfonyl)imide salts via the telescopic process
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The preparation of aryl iodides in a telescopic reaction using tert-butyl nitrite as a diazotization reagent and a mixture of bis(trifluoromethane) sulfonamide and glacial acetic acid as a mild acidic agent in ethanol followed by iododediazoniation with tetraethylammonium iodide in water was investigated. The current method has other advantages such as minimized waste by avoiding solvent for the purification of products in diazotization step, simple experimental procedure, and good yield of the sterically hindered aryl amines, metal and strong acid-free waste and environmentally benign conditions. The noteworthy features of this study are the preparation of stable arenediazonium bis(trifluoromethylsulfonyl)imide salts that can be used with no significant loss activity after 1?week and bis(trifluoromethane)sulfonamide was recovered in high yields from reactions.
- Khaligh, Nader Ghaffari
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- Generation of Phosphoranyl Radicals via Photoredox Catalysis Enables Voltage-Independent Activation of Strong C-O Bonds
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Despite the prevalence of alcohols and carboxylic acids as functional groups in organic molecules and the potential to serve as radical precursors, C-O bonds remain difficult to activate. We report a synthetic strategy for direct access to both alkyl and acyl radicals from these ubiquitous functional groups via photoredox catalysis. This method exploits the unique reactivity of phosphoranyl radicals, generated from a polar/SET crossover between a phosphine radical cation and an oxygen-centered nucleophile. We show the desired reactivity in the reduction of benzylic alcohols to the corresponding benzyl radicals with terminal H atom trapping to afford the deoxygenated products. Using the same method, we demonstrate access to synthetically versatile acyl radicals, which enables the reduction of aromatic and aliphatic carboxylic acids to the corresponding aldehydes with exceptional chemoselectivity. This protocol also transforms carboxylic acids to heterocycles and cyclic ketones via intramolecular acyl radical cyclizations to forge C-O, C-N, and C-C bonds in a single step.
- Stache, Erin E.,Ertel, Alyssa B.,Rovis, Tomislav,Doyle, Abigail G.
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p. 11134 - 11139
(2018/11/21)
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- N-Iodosuccinimide (NIS) in Direct Aromatic Iodination
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N-Iodosuccinimide (NIS) in pure trifluoroacetic acid (TFA) offers a time-efficient and general method for the iodination of a wide range of mono- and disubstituted benzenes at room temperature, as demonstrated in this paper. The starting materials were generally converted into mono-iodinated products in less than 16 hours at room temperature, without byproducts. A few deactivated substrates needed addition of sulfuric acid to increase the reaction rate. Another exception was methoxybenzenes that preferentially were iodinated by NIS in acetonitrile with only catalytic amounts of TFA.
- Bergstr?m, Maria,Suresh, Ganji,Naidu, Veluru Ramesh,Unelius, C. Rikard
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p. 3234 - 3239
(2017/06/21)
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- Simple and Efficient Generation of Aryl Radicals from Aryl Triflates: Synthesis of Aryl Boronates and Aryl Iodides at Room Temperature
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Despite the wide use of aryl radicals in organic synthesis, current methods to prepare them from aryl halides, carboxylic acids, boronic acids, and diazonium salts suffer from limitations. Aryl triflates, easily obtained from phenols, are promising aryl radical progenitors but remain elusive in this regard. Inspired by the single electron transfer process for aryl halides to access aryl radicals, we developed a simple and efficient protocol to convert aryl triflates to aryl radicals. Our success lies in exploiting sodium iodide as the soft electron donor assisted by light. This strategy enables the scalable synthesis of two types of important organic molecules, i.e., aryl boronates and aryl iodides, in good to high yields, with broad functional group compatibility in a transition-metal-free manner at room temperature. This protocol is anticipated to find potential applications in other aryl-radical-involved reactions by using aryl triflates as aryl radical precursors.
- Liu, Wenbo,Yang, Xiaobo,Gao, Yang,Li, Chao-Jun
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supporting information
p. 8621 - 8627
(2017/07/06)
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- Visible-Light Photoredox-Catalyzed Aminosulfonylation of Diaryliodonium Salts with Sulfur Dioxide and Hydrazines
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A photoredox-catalyzed three-component synthesis of N-aminosulfonamides starting from diaryliodonium salts, hydrazines and sulfur dioxide is reported. This reaction proceeds under mild conditions at room temperature and is driven by visible light. A simple bisulfite salt can be used as a readily available and easy-to-handle sulfur dioxide source. Mechanistic studies support a catalytic photoredox pathway with the diaryliodonium salt as convenient source for aryl radicals. (Figure presented.).
- Liu, Nai-Wei,Liang, Shuai,Manolikakes, Georg
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supporting information
p. 1308 - 1319
(2017/04/18)
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- Copper-catalyzed conversion of aryl and heteroaryl bromides into the corresponding iodide
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An efficient method for the synthesis of aryl and heteroaryl iodides is described in this study. The reactions of aryl and heteroaryl bromides with potassium iodide proceeded smoothly in the presence of a copper catalyst under mild reaction conditions to produce the corresponding iodides in satisfactory to excellent yields.
- Feng, Xiujuan,Li, Lingyu,Yu, Xiaoqiang,Yamamoto, Yoshinori,Bao, Ming
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p. 129 - 132
(2016/07/06)
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- Synthesis method of p-iodotoluene serving as methotrexate drug intermediate
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A synthesis method of p-iodotoluene serving as a methotrexate drug intermediate comprises steps as follows: (i) 500 ml of a phosphoric acid solution with certain concentration and 1.2 mol of p-toluidine (2) are added to a 3L reaction container provided with a stirrer, a thermometer and a dropping funnel, the temperature of the solution is reduced to 3-6 DEG C after dissolution, 1.1-1.2 mol of potassium sulfite is added and dissolved in 300 ml of water, a potassium sulfite solution is prepared, the reaction temperature is controlled to be 15-18 DEG C, then, the mixture continuously reacts for 10-15 min, 1.1-1.15 mol of sodium iodate is slowly added and dissolved in 230 ml of water, a sodium iodate solution is prepared, the temperature of the solution is adjusted to be 80-85 DEG C, the solution is kept at the temperature until no bubbles are generated, the temperature of the solution is reduced to 25-30 DEG C, a supernatant liquid is poured out, 0.2-0.3 mol of potassium nitrite is added to remaining oily substances, a water layer is colorless, 300 ml of a sodium carbonate solution with certain concentration is added, the pH value of the solution is 8-9, water steam is distilled until no oily substances are distilled, the temperature of the solution is reduced to 5-8 DEG C, orange-yellow crystals are obtained, filtered, washed with a detergent and dewatered with a dewatering agent, and p-iodotoluene is obtained.
- -
-
Paragraph 0014; 0015
(2017/03/08)
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- Easy Access to Difluoromethylene-Containing Arene Analogues through Palladium-Catalysed C–H Olefination
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An efficient palladium-catalysed ortho-C–H olefination of α,α-difluorophenylacetic acid derivatives using 8-aminoquinoline as a bidentate directing group has been developed. A range of olefinated arenes can thus be synthesized in a concise way. This reaction provides an easy and straightforward route to a panel of difluoromethylated arene analogues in moderate to good yields, with a satisfactory tolerance of common functional groups. Transformation of the products into a variety of other difluoromethylene-containing compounds demonstrates the utility of this method.
- Shao, Changdong,Shi, Guangfa,Zhang, Yanghui
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supporting information
p. 5529 - 5538
(2016/11/25)
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- Diarylation of chalcogen elements using arylboronic acids via copper- or palladium-catalyzed oxidative coupling
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Transition metal-catalyzed diarylations of sulfur, selenium and tellurium were achieved using arylboronic acids in air. A copper-catalyzed reaction of sulfur or selenium efficiently yielded numerous symmetrical diaryl sulfides or selenides in the presence of NH4BF4. However, the diarylation of tellurium was not possible using this method, and required a palladium catalyst in the presence of KI and air for the reaction to proceed.
- Taniguchi, Nobukazu
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p. 5818 - 5823
(2016/08/30)
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- A General and Mild Copper(I)-Catalyzed Three-Component Reaction of Cyanamides, Amines, and Diaryliodonium Triflates
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A highly efficient copper-catalyzed three-component reaction of cyanamides, amines, and diaryliodonium triflates was developed for the synthesis of guanidines. The mild reaction accommodates both aromatic and aliphatic amines and provides the products in good yields with good functional group tolerance. Moreover, it was demonstrated that C-H activation of the arenes could be realized for the direct preparation of guanidines.
- Li, Jihui,Wang, Hongxing,Hou, Yifeng,Yu, Weiguang,Xu, Shuying,Zhang, Yucang
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supporting information
p. 2388 - 2392
(2016/06/01)
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- Transition-metal free N-arylation of cyanamides by diaryliodonium triflates in aqueous media
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An operationally simple protocol is established for the synthesis of disubstituted cyanamides through the transition-metal free N-arylation of cyanamides by diaryliodonium triflates in aqueous media. Both alkyl and aryl cyanamides are well compatible with the mild reaction conditions. The one-pot synthesis of ureas is also possible through sequential arylation and hydrolysis of cyanamides, diaryliodonium triflates and H2O with good yields.
- Li, Jihui,Zheng, Xinyi,Li, Wei,Zhou, Wei,Zhu, Wen,Zhang, Yucang
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supporting information
p. 77 - 80
(2016/01/12)
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- En Route to a Practical Primary Alcohol Deoxygenation
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A long-standing scientific challenge in the field of alcohol deoxygenation has been direct catalytic sp3 C-O defunctionalization with high selectivity and efficiency, in the presence of other functionalities, such as free hydroxyl groups and amines widely present in biological molecules. Previously, the selectivity issue had been only addressed by classic multistep deoxygenation strategies with stoichiometric reagents. Herein, we propose a catalytic late-transition-metal-catalyzed redox design, on the basis of dehydrogenation/Wolff-Kishner (WK) reduction, to simultaneously tackle the challenges regarding step economy and selectivity. The early development of our hypothesis focuses on an iridium-catalyzed process efficient mainly with activated alcohols, which dictates harsh reaction conditions and thus limits its synthetic utility. Later, a significant advancement has been made on aliphatic primary alcohol deoxygenation by employing a ruthenium complex, with good functional group tolerance and exclusive selectivity under practical reaction conditions. Its synthetic utility is further illustrated by excellent efficiency as well as complete chemo- and regio-selectivity in both simple and complex molecular settings. Mechanistic discussion is also included with experimental supports. Overall, our current method successfully addresses the aforementioned challenges in the pertinent field, providing a practical redox-based approach to the direct sp3 C-O defunctionalization of aliphatic primary alcohols.
- Dai, Xi-Jie,Li, Chao-Jun
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supporting information
p. 5433 - 5440
(2016/05/19)
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- An alternative to the Sandmeyer approach to aryl iodides
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Iodoarenes are important synthons for a wide range of organic transformations. Here we report a general strategy to prepare singly iodinated electron-rich aromatic compounds through the intermediacy of diaryliodonium salts. This process, which incorporates a phase separation that greatly simplifies product purification, is an attractive replacement for the Sandmeyer approach to iodoarenes that are otherwise difficult to access.
- Hu, Bao,Miller, William H.,Neumann, Kiel D.,Linstad, Ethan J.,DiMagno, Stephen G.
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p. 6394 - 6398
(2015/04/22)
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- Acetonitrile as a cyanating reagent: Cu-catalyzed cyanation of arenes
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A novel approach to the Cu-catalyzed cyanation of simple arenes using acetonitrile as an attractive cyano source has been documented. The C-H functionalization of arenes without directing groups involves a sequential iodination/cyanation to give the desired aromatic nitriles in good yields. A highly efficient Cu/TEMPO system for acetonitrile C-CN bond cleavage has been discovered. TEMPO is used as a cheap oxidant and enables the reaction to be catalytic in copper. Moreover, TEMPOCH2CN 6 has been identified as the active cyanating agent and shows high reactivity for forming the -CN moiety.
- Zhu, Yamin,Zhao, Mengdi,Lu, Wenkui,Li, Linyi,Shen, Zengming
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p. 2602 - 2605
(2015/06/16)
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- Compartmentalization of incompatible reagents within Pickering emulsion droplets for one-pot cascade reactions
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It is a dream that future synthetic chemistry can mimic living systems to process multistep cascade reactions in a one-pot fashion. One of the key challenges is the mutual destruction of incompatible or opposing reagents, for example, acid and base, oxidants and reductants. A conceptually novel strategy is developed here to address this challenge. This strategy is based on a layered Pickering emulsion system, which is obtained through lamination of Pickering emulsions. In this working Pickering emulsion, the dispersed phase can separately compartmentalize the incompatible reagents to avoid their mutual destruction, while the continuous phase allows other reagent molecules to diffuse freely to access the compartmentalized reagents for chemical reactions. The compartmentalization effects and molecular transport ability of the Pickering emulsion were investigated. The deacetalization-reduction, deacetalization-Knoevenagel, deacetalization-Henry and diazotization-iodization cascade reactions demonstrate well the versatility and flexibility of our strategy in processing the one-pot cascade reactions involving mutually destructive reagents. (Figure Presented).
- Yang, Hengquan,Fu, Luman,Wei, Lijuan,Liang, Jifen,Binks, Bernard P.
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supporting information
p. 1362 - 1371
(2015/02/19)
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- Synthesis and antiproliferative activity of novel 4-substituted-phenoxy-benzamide derivatives
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A series of novel 4-substituted-phenoxy-benzamide derivatives bearing an aryl cycloaliphatic amine moiety were synthesized and evaluated for antiproliferative activity against SW620, HT29 and MGC803 cancer cell lines in vitro. The pharmacological data demonstrated that the majority of target compounds exhibited moderate efficacy in HT29 and MGC803 cell lines. Compound 10c showed promising inhibition of hedgehog (Hh) signaling pathway in an Hh-related assay. In addition, the superposition pattern of 10c showed a good fit for a pharmacophoric model generated by Hh inhibitors and provided a basis for further structural optimization.
- Sun, Chi-Yu,Li, Yang-Sheng,Shi, Ai-Long,Li, Ya-Fei,Cao, Rui-Fang,Ding, Huai-Wei,Yin, Qing-Qing,Zhang, Li-Juan,Zheng, Hua-Chuan,Song, Hong-Rui
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supporting information
p. 1307 - 1310
(2015/12/31)
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- O,N,N-Pincer ligand effects on oxidatively induced carbon-chlorine coupling reactions at palladium
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The syntheses of two families of sterically tuneable O,N,N pro-ligands are reported, namely the 2-(phenyl-2′-ol)-6-imine-pyridines, 2-(C6H4-2′-OH),6-(CMeNAr)C5H3N [Ar = 4-i-PrC6H4 (HL1a), 2,6-i-Pr2C6H3 (HL1b)] and the 2-(phenyl-2′-ol)-6-(amino-prop-2-yl)pyridines, 2-(C6H4-2′-OH),6-(CMe2NHAr)C5H3N [Ar = 4-i-PrC6H4 (HL2a), 2,6-i-Pr2C6H3 (HL2b)], using straightforward synthetic approaches and in reasonable overall yields. Interaction of HL1a/c and HL2a/b with palladium(ii) acetate affords the O,N,N-pincer complexes, [{2-(C6H4-2′-O)-6-(CMeNAr)C5H3N}Pd(OAc)] (Ar = 4-i-PrC6H4 (1a), 2,6-i-Pr2C6H3 (1b)) and [{2-(C6H4-2′-O)-6-(CMe2NHAr)C5H3N}Pd(OAc)] (Ar = 4-i-PrC6H4 (2a), 2,6-i-Pr2C6H3 (2b)), which can be readily converted to their chloride derivatives, [{2-(C6H4-2′-O)-6-(CMeNAr)C5H3N}PdCl] (Ar = 4-i-PrC6H4 (3a), 2,6-i-Pr2C6H3 (3b)) and [{2-(C6H4-2′-O)-6-(CMe2NHAr)C5H3N}PdCl] (Ar = 4-i-PrC6H4 (4a), 2,6-i-Pr2C6H3 (4b)), respectively, on reaction with an aqueous sodium chloride solution. Treating each of 3a, 3b, 4a and 4b with two equivalents of di-p-tolyliodonium triflate at 100 °C in a toluene/acetonitrile mixture affords varying amounts of 4-chlorotoluene along with the 4-iodotoluene by-product with the conversions highly dependent on the steric and backbone properties of the pincer complex employed (viz.4a > 3a > 4b > 3b); notably, the least sterically bulky and most flexible amine-containing 4a reaches 90% conversion to 4-chlorotoluene in 15 h as opposed to 17% for imine-containing 3b. In the case of 3a, the inorganic palladium species recovered from the reaction has been identified as the Pd(ii) salt [{2-(C6H4-2′-O)-6-(CMeN(4-i-PrC6H4)C5H3N}Pd(NCMe)][O3SCF3] (5a), which was independently prepared by the reaction of 3a with silver triflate in acetonitrile. Single crystal X-ray structures are reported for HL1a, HL2a, 1a, 1b, 2a, 2b, 3a and 5a. This journal is
- Wright, Luka A.,Hope, Eric G.,Solan, Gregory A.,Cross, Warren B.,Singh, Kuldip
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p. 6040 - 6051
(2015/03/30)
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- Efficient and direct iodination of alkyl benzenes using polymer/HIO4 and I2 under mild condition
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An efficient and rapid method has been found for the iodination of aromatic compounds using iodine and polymer-supported periodic acid (PSPIA) as an oxidant under mild aprotic conditions. The reagent after the completion of the reaction was easily removed by filtration and was regenerated for further use. This method has some advantages such as: mild reaction conditions, straight forward procedure, inexpensive method, high yields and one-pot conversion.
- Bahrami-Nasab, Sepideh,Nazifi, S. Mohamad Reza,Pourali, Ali Reza
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p. 305 - 308
(2014/06/24)
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- Standard enthalpies of formation of 4-methylbiphenyl and 4,4-dimethylbiphenyl
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The energies of combustion of 4-methylbiphenyl and 4,4-dimethylbiphenyl in the crystal state were measured in a precision calorimeter equipped with a self-sealing bomb at 298.15 K. The enthalpies of vaporization of these substances were measured in an isothermal heat-conducting Calvet microcalorimeter. Standard enthalpies of formation were calculated for 4-methylbiphenyl and 4,4-dimethylbiphenyl in the crystal, liquid, and gas states.
- Pimenova,Pashchenko,Miroshnichenko,Nesterov
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p. 557 - 561
(2014/05/06)
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- Gold(I)-catalyzed iodination of arenes
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A wide variety of electron-rich arenes were efficiently converted into the corresponding iodinated compounds via a gold(I)-catalyzed reaction under mild conditions. Georg Thieme Verlag Stuttgart. New York.
- Leboeuf, David,Ciesielski, Jennifer,Frontier, Alison J.
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supporting information
p. 399 - 402
(2014/03/21)
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- Aryl diazonium nanomagnetic sulfate and potassium iodide: An iodination process
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A simple and efficient procedure for the synthesis of iodoarenes is developed which involves the sequential diazotization-iodination of aromatic amines with sodium nitrite, nanomagnetic supported sulfonic acid, and potassium iodide under solvent-free conditions at room temperature.
- Kolvari, Eskandar,Amoozadeh, Ali,Koukabi, Nadiya,Otokesh, Somayeh,Isari, Mohsen
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supporting information
p. 3648 - 3651
(2014/06/23)
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- Acidic ionic liquid supported on silica-coated magnetite nanoparticles as a green catalyst for one-pot diazotization-halogenation of the aromatic amines
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Acidic ionic liquid was immobilized on silica-coated magnetite nanoparticles (Fe3O4@SILnP) and used as an efficient heterogeneous catalyst for the diazotization-iodination reaction of different aromatic amines under solvent-free conditions at room temperature. The diazonium salts that are formed by this catalyst are stable at room temperature and react rapidly with sodium iodide to produce aryl iodides in good to excellent yields. This method has some advantages such as low pollution, rapid access to products, simple work-up and easy separation of catalyst from the reaction mixture.
- Isaad, Jalal
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p. 49333 - 49341
(2014/12/10)
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- Photoinitiated oxidative addition of CF3I to gold(I) and facile aryl-CF3 reductive elimination
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Herein we report the mechanism of oxidative addition of CF3I to Au(I), and remarkably fast Caryl-CF3 bond reductive elimination from Au(III) cations. CF3I undergoes a fast, formal oxidative addition to R3PAuR' (R = Cy, R' = 3,5-F2-C 6H4, 4-F-C6H4, C6H 5, 4-Me-C6H4, 4-MeO-C6H4, Me; R = Ph, R' = 4-F-C6H4, 4-Me-C6H 4). When R' = aryl, complexes of the type R3PAu(aryl) (CF3)I can be isolated and characterized. Mechanistic studies suggest that near-ultraviolet light (λmax = 313 nm) photoinitiates a radical chain reaction by exciting CF3I. Complexes supported by PPh3 undergo reversible phosphine dissociation at 110 °C to generate a three-coordinate intermediate that undergoes slow reductive elimination. These processes are quantitative and heavily favor C aryl-I reductive elimination over Caryl-CF3 reductive elimination. Silver-mediated halide abstraction from all complexes of the type R3PAu(aryl)(CF3)I results in quantitative formation of Ar-CF3 in less than 1 min at temperatures as low as -10 °C.
- Winston, Matthew S.,Wolf, William J.,Toste, F. Dean
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p. 7777 - 7782
(2014/06/10)
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- Metal-free iodination of arylboronic acids and the synthesis of biaryl derivatives
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A simple, general and efficient method is developed for the metal-free iodination of arylboronic acids. The protocol uses very cheap molecular iodine as the halide source and potassium carbonate as the base. The method is highly tolerant of various functional groups present in the substrates. Importantly, the iodination strategy can also be applied very effectively in the one-pot, two-step synthesis of biaryl derivatives. Georg Thieme Verlag Stuttgart New York.
- Niu, Liting,Zhang, Hao,Yang, Haijun,Fu, Hua
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supporting information
p. 995 - 1000
(2014/05/06)
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- Mizoroki-Heck reactions of methyl acrylate in presence of a palladated rasta resin
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Mizoroki-Heck cross-couplings of aryl halides in the presence of a palladium catalyst supported on a rasta resin bearing diphenylphosphanyl ligands are reported. In particular, we show that tiny amounts of soluble palladium species leached from the polymeric support catalyze the reaction. A one-pot two steps preparation of alkenes from aryl bromides using a Finkelstein halogen exchange reaction is also described.
- Derible, Antoine,Becht, Jean-Michel,Le Drian, Claude
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p. 4207 - 4209
(2013/07/26)
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- The oxidative halogenations of arenes in water using hydrogen peroxide and halide salts over an ionic catalyst containing sulfo group and hexafluorotitanate
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An ionic compound, bis[1-methyl-3-(3′-sulfopropyl)imidazolium] hexafluorotitanate (1), was proved to be the efficient and recyclable catalyst for the oxidative halogenations of arenes in water using H2O 2 as the oxidant and halide salts as the halogenation sources. The mono-halogenated products were obtained selectively by this method. The synergetic catalytic effect coming from the two incorporated functionalities of SO3H and [TiF6]2- was manifested in 1. The halogenation rate catalyzed by 1 was in the ranking of NaBr NaCl > KI. The UV-vis and FT-IR analyses indicated that the successful formation and regeneration of the active peroxo-Ti species (1A) with the aid of proton acid guaranteed the recycling uses of 1.
- Wang, Ling,Wang, Sa-Sa,Vo-Thanh, Giang,Liu, Ye
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- Bronsted acidic ionic liquid accelerated halogenation of organic compounds with N-halosuccinimides (NXS)
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The Bronsted-Acidic ionic liquid 1-methyl-3-(4-sulfobutyl) imidazolium triflate [BMIM(SO3H)][OTf] was demonstrated to act efficiently as solvent and catalyst for the halogenation of activated organic compounds with N-halosuccinimides (NXS) under mild conditions with short reaction times. Methyl aryl ketones were converted into a-halo and a,a-dihaloketones, depending on the quantity of NXS used. Ketones with activated aromatic rings were selectively halogenated, however in some cases mixtures of a-halogenated ketone and ring-halogenated ketones were obtained. Activated aromatics were regioselectively ring halogenated to give mono- and dihalo-substituted products. The [BMIM(SO3H)][OTf] ionic liquid (IL-A) was successfully reused eight times in a representative monohalogenation reaction with no noticeable decrease in efficiency. An effective halogenation scale-up in this IL is also presented. The reactivity trend and the observed chemo- and regioselectiivities point to an ET process in these IL-promoted halofunctionalization reactions.
- Vrazic, Dejan,Jereb, Marjan,Laali, Kenneth K.,Stavber, Stojan
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- Nitrite ionic liquid as a new reagent for in situ synthesis of aryl iodides and azides
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A new ionic liquid, 1-methyl-3-(2-[2-(1-methyl-1H-imidazol-3-ium-3-yl)ethyloxy] ethyl)-1H-imidazol-3-ium dinitrite, was synthesized. This ionic liquid was used as a convenient nitrosonium source in diazotization of aryl amines into their corresponding diazonium salts, which were converted into aryl iodides and aryl azides using potassium iodide or sodium azide, respectively. Various aryl amines possessing electron-withdrawing groups or electron-donating groups were converted into the corresponding aryl iodides and aryl azides in excellent yields. Advantages of this methodology are the use of mild reaction conditions, short reaction times, and avoiding the use of toxic solvents.
- Eshghi, Hossein,Bakavoli, Mehdi,Ghasemzadeh, Marjan
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p. 3999 - 4007
(2015/06/08)
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- Iron-catalyzed cross-coupling reaction: Recyclable heterogeneous iron catalyst for selective olefination of aryl iodides in poly(ethylene glycol) medium
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An environmentally friendly iron-based catalyst supported on acac-functionalized silica was successfully prepared and evaluated as a heterogeneous catalyst for Mizoroki-Heck reaction of aryl iodides and olefins. Our catalytic system showed good activities that were comparable to that of palladium catalysts. The catalyst was simply recovered from the reaction mixture and recycled five times. Furthermore, the reaction was carried out in poly(ethylene glycol) as a green solvent. Interestingly, using this catalyst, aryl iodides were selectively olefinated in the presence of aryl bromides.
- Hajipour, Abdol Reza,Azizi, Ghobad
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supporting information
p. 1030 - 1034
(2013/07/26)
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