- 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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- Two-photon absorbing compounds and methods of making same
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A two-photon absorbing (TPA) compound is provided, along with a method of making same. The TPA compound has a general structural formula: where A is an acceptor moiety that is connected to m number of diarylaminofluorene arms (m=1-3); in each diarylaminofluorene arms, R is selected from linear or branched alkyl chains having a general formula CnH2n+1, where n is in a range from 2 to 25; where R1, R2, and R3 are independently selected from H or C1-C4 alkyls; where R4 is selected from C1-C5 alkyls; and wherein R5 through R10 are independently selected from H, alkoxyls, alkyls, or aryls. A may be benzothiazol-2-yl, benzo[1,2-d:4,5-d′]bisthiazole-2,6-diyl, thiazolo[5,4-d]thiazole-2,5-diyl-, 1,3,5-triazine-2,4,6-triyl, 1,3,5-triazine-2,4,6-triyl, benzo[1,2-d:3,4-d′:5,6-d″]tristhiazole-2,5,8-triyl-, or dithieno[3,2-b:2′,3′-d]thiophene-2,6-diyl-.
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Page/Page column 21
(2018/11/21)
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- Mechanism and selectivity in nickel-catalyzed cross-electrophile coupling of aryl halides with alkyl halides
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The direct cross-coupling of two different electrophiles, such as an aryl halide with an alkyl halide, offers many advantages over conventional cross-coupling methods that require a carbon nucleophile. Despite its promise as a versatile synthetic strategy, a limited understanding of the mechanism and origin of cross selectivity has hindered progress in reaction development and design. Herein, we shed light on the mechanism for the nickel-catalyzed cross-electrophile coupling of aryl halides with alkyl halides and demonstrate that the selectivity arises from an unusual catalytic cycle that combines both polar and radical steps to form the new C-C bond.
- Biswas, Soumik,Weix, Daniel J.
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supporting information
p. 16192 - 16197
(2013/11/19)
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- METHOD OF PRODUCING IODIZING AGENT, AND METHOD OF PRODUCING AROMATIC IODINE COMPOUND
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A method of the present invention, for producing an iodizing agent, includes the step of electrolyzing iodine molecules in a solution by using an acid as a supporting electrolyte. This realizes (i) a method of producing an iodine cation suitable for use as an iodizing agent that does not require a sophisticated separation operation after iodizing reaction is completed, and (ii) an electrolyte used in the method. Further, a method of the present invention, for producing an aromatic iodine compound, includes the step of causing an iodizing agent, and an aromatic compound whose nucleus has one or more substituent groups and two or more hydrogen atoms, to react with each other under the presence of a certain ether compound. This realizes such a method of producing an aromatic iodine compound that position selectivity in iodizing reaction of an aromatic compound is improved.
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Page/Page column 9
(2010/05/13)
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- Discovery of selective nonpeptidergic neuropeptide FF2 receptor agonists
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We report the discovery and initial characterization of a novel class of selective NPFF2 agonists. HTS screening using R-SAT, a whole cell based functional assay, identified a class of aryliminoguanidines as NPFF1 and NPFF2 ligands. Subsequent optimizatio
- Gaubert, Gilles,Bertozzi, Fabio,Kelly, Nicholas M.,Pawlas, Jan,Scully, Audra L.,Nash, Norman R.,Gardell, Luis R.,Lameh, Jelveh,Olsson, Roger
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body text
p. 6511 - 6514
(2010/03/26)
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- Revealing a second transmetalation step in the Negishi coupling and its competition with reductive elimination: Improvement in the interpretation of the mechanism of biaryl syntheses
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This paper presents an experimental and theoretical investigation of the Pd-catalyzed Negishi coupling reaction and reveals a novel second transmetalation reaction between an Ar1-Pd-Ar2 species and the organozinc reagent Ar2-ZnX. Understanding of this second step reveals how homocoupling and dehalogenation products are formed. Thus, the second transmetalation generates Ar2PdAr2 and Ar 1ZnCl, which upon reductive elimination and hydrolysis, respectively, give the homocoupling product Ar2-Ar2 and the dehalogenation product Ar1H. The ratio of the cross-coupling product Ar1-Ar2 and the homocoupling product Ar 2-Ar2 is determined by competition between the second transmetalation and reductive elimination steps. This mechanism is further supported by density functional theoretical calculations. Calculations on a series of reactions suggest a strategy in controlling the selectivity of cross-coupling and homocoupling pathways, which we have experimentally verified.
- Liu, Qiang,Lan, Yu,Liu, Jing,Li, Gang,Wu, Yun-Dong,Lei, Aiwen
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supporting information; experimental part
p. 10201 - 10210
(2009/12/08)
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- Practical electrochemical iodination of aromatic compounds
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A practical method for electrochemical iodination of aromatic compounds was developed. The method involves the generation of I+ by electrochemical oxidation of I2 in CH3CN using H 2SO4 as supporting electrolyte followed by the reaction with aromatic compounds. The para/ortho selectivity for the reaction of mono-substituted benzenes was significantly improved using dimethoxyethane as cosolvent in the second step. The reaction with highly reactive aromatic compounds led to the formation of significant amounts of diiodo compounds in a macrobatch reactor. This problem was solved by fast 1:1 mixing of I+ with an aromatic compound using a microflow system consisting of a T-shaped micromixer and a microtube reactor.
- Kataoka, Kazuhide,Hagiwara, Yuji,Midorikawa, Koji,Suga, Seiji,Yoshida, Jun-Ichi
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p. 1130 - 1136
(2013/01/03)
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- A direct palladium-catalyzed route to selectively substituted carbazoles through sequential C-C and C-N bond formation: Synthesis of carbazomycin A
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The present paper offers a synthetically simple one-pot procedure for the catalytic preparation of the biologically interesting class of carbazoles. The new procedure is based on the combined catalysis of palladium and norbornene starting from o-substituted iodoarenes and N-sulfonylated or N-acetylated o-bromoanilines. A well-known member of this class, carbazomycin A, has been successfully prepared.
- Della Ca', Nicola,Sassi, Giovanni,Catellani, Marta
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supporting information; scheme or table
p. 2179 - 2182
(2009/10/02)
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- Efficient method for the preparation of aromatic bromides and iodides by ferrocenium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate-catalyzed halogenation with bromine and iodine monochloride
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Direct iodination and bromination of various aromatic compounds with 1.1-2.0 molar amounts of iodine monochloride (ICl) and 1.1-3.0 molar amounts of bromine proceeded smoothly to afford the corresponding aromatic iodides and bromides, respectively, in good to excellent yields by using 0.05 molar amount of ferrocenium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, Cp2FeB[3,5-(CF3)2C6H 3]4 (1), in the presence of ZnO. Iodination of toluene in the co-existence of 0.5 molar amount of DDQ also proceeded to give iodotoluenes in high yield.
- Kitagawa, Hideo,Shibata, Tsuyoshi,Matsuo, Jun-Ichi,Mukaiyama, Teruaki
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p. 339 - 345
(2007/10/03)
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- Iodination of aromatic compounds with iodine monochloride in aqueous sulfuric acid
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Iodine monochloride in aqueous sulfuric acid turned out to be a convenient and general reagent for preparative iodination of alkylbenzenes, phenol ethers, and aromatic amines. The relative selectivity and activity of iodine monochloride in aqueous solutions of sulfuric acid with various concentrations were determined using toluene as model substrate. Raising the sulfuric acid concentration results in considerable increase of the electrophilicity of ICl. Effective sulfuric acid concentrations were determined for specific substrate series. Iodine monochloride in aqueous sulfuric acid shows enhanced selectivity in the synthesis of monoiodo derivatives.
- Chaikovskii,Filimonov,Kharlova,Chernova,Sharapova
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p. 666 - 670
(2007/10/03)
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