624-31-7Relevant articles and documents
Palladium-Catalyzed Decarbonylative Iodination of Aryl Carboxylic Acids Enabled by Ligand-Assisted Halide Exchange
Boehm, Philip,Cacherat, Bastien,Lee, Yong Ho,Martini, Tristano,Morandi, Bill
supporting information, p. 17211 - 17217 (2021/07/02)
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.
Metal-Organic Framework-Confined Single-Site Base-Metal Catalyst for Chemoselective Hydrodeoxygenation of Carbonyls and Alcohols
Antil, Neha,Kumar, Ajay,Akhtar, Naved,Newar, Rajashree,Begum, Wahida,Manna, Kuntal
supporting information, p. 9029 - 9039 (2021/06/28)
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.
Synthesis of biaryl compounds via Suzuki homocoupling reactions catalyzed by metal organic frameworks encapsulated with palladium nanoparticles
Bao, Yan-Sai,Cui, Xin-Yu,Han, Zheng-Bo,Li, Xin,Tang, Hong,Yang, Ming,Zhang, Yu-Yang,Zhao, Kun,Zhou, Mei-Li
, (2020/12/17)
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.
The graphite-catalyzed: ipso -functionalization of arylboronic acids in an aqueous medium: metal-free access to phenols, anilines, nitroarenes, and haloarenes
Badgoti, Ranveer Singh,Dandia, Anshu,Parewa, Vijay,Rathore, Kuldeep S.,Saini, Pratibha,Sharma, Ruchi
, p. 18040 - 18049 (2021/05/29)
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.
Green synthesis method for p-iodotoluene
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Paragraph 0031-0040, (2020/04/17)
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.
Arene diazonium saccharin intermediates: A greener and cost-effective alternative method for the preparation of aryl iodide
Ghaffari Khaligh, Nader,Rafie Johan, Mohd,Shahnavaz, Zohreh,Zaharani, Lia
, p. 535 - 542 (2020/06/01)
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.
Generation of Organozinc Reagents from Arylsulfonium Salts Using a Nickel Catalyst and Zinc Dust
Yamada, Kodai,Yanagi, Tomoyuki,Yorimitsu, Hideki
, p. 9712 - 9718 (2021/01/09)
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.
Orthogonal Stability and Reactivity of Aryl Germanes Enables Rapid and Selective (Multi)Halogenations
Deckers, Kristina,Fricke, Christoph,Schoenebeck, Franziska
supporting information, p. 18717 - 18722 (2020/08/25)
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.
Methane Generation and Reductive Debromination of Benzylic Position by Reconstituted Myoglobin Containing Nickel Tetradehydrocorrin as a Model of Methyl-coenzyme M Reductase
Hayashi, Takashi,Miyazaki, Yuta,Oohora, Koji
supporting information, p. 11995 - 12004 (2020/09/15)
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.
Generation of Organozinc Reagents by Nickel Diazadiene Complex Catalyzed Zinc Insertion into Aryl Sulfonates
Klein, Philippe,Lechner, Vivien Denise,Schimmel, Tanja,Hintermann, Lukas
supporting information, p. 176 - 180 (2019/12/11)
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.
