- 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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- Arylation of aryllithiums with: S-arylphenothiazinium ions for biaryl synthesis
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Aryllithiums are one of the most common and important aryl nucleophiles; nevertheless, methods for arylation of aryllithums to produce biaryls have been limited. Herein, we report arylation of aryllithiums with S-arylphenothiazinium ions through selective
- Morofuji, Tatsuya,Yoshida, Tatsuki,Tsutsumi, Ryosuke,Yamanaka, Masahiro,Kano, Naokazu
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supporting information
p. 13995 - 13998
(2020/11/21)
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- Organic electroluminescent materials and devices
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A compound according to a formula I and devices incorporating the same are described. The compound according to the formula I can have the structure: wherein X is Si or Ge; R1 and R2 represent mono, di, tri, tetra, or penta substitutions or no substitution; R3, R4 represent mono, di, tri, or tetra substitutions or no substitution; R1 and R2 are optionally joined to form a ring, which may be further substituted; L is a single bond or comprises an aryl or heteroaryl group having from 5-20 carbon atoms, which is optionally further substituted; and A is an aromatic group. A contains a group selected from the group consisting of indole, carbazole, benzofuran, dibenzofuran, benzothiophene, dibenzothiophene, benzoselenophene, dibenzoselenophene, triphenylene, azacarbazole, azadibenzofuran, azadibenzothiophene, azadibenzoselenophene, azatriphenylene, and combinations thereof, which are optionally further substituted. The device can include the compound according to Formula I in an organic layer.
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Page/Page column 127
(2015/02/18)
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- Photo-induced Metal-Catalyst-Free Aromatic Finkelstein Reaction
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The facile iodination of aromatic compounds under mild conditions is a great challenge for both organic and medicinal chemistry. Particularly, the synthesis of functionalized aryl iodides by light has long been considered impossible due to their photo-lability, which actually makes aryl iodides popular starting materials in many photo-substitution reactions. Herein, a photo-induced halogen exchange in aryl or vinyl halides has been discovered for the first time. A broad scope of aryl iodides can be prepared in high yields at room temperature under exceptionally mild conditions without any metal or photo-redox catalysts. The presence of a catalytic amount of elemental iodine could promote the reaction significantly.
- Li, Lu,Liu, Wenbo,Zeng, Huiying,Mu, Xiaoyue,Cosa, Gonzalo,Mi, Zetian,Li, Chao-Jun
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supporting information
p. 8328 - 8331
(2015/07/15)
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- Synthesis of substituted [8]cycloparaphenylenes by [2 + 2 + 2] cycloaddition
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A new modular approach to the smallest substituted cycloparaphenylenes (CPPs) is presented. This versatile method permits access to substituted CPPs, choosing the substituent at a late stage of the synthesis. Variously substituted [8]CPPs have been synthesized, and their properties analyzed. The structural characteristics of substituted CPPs are close to those of unsubstituted CPPs. However, their optoelectronic behavior differs remarkably due to the larger torsion angle between the phenyl units.
- Tran-Van, Anne-Florence,Huxol, Elena,Basler, Jonathan M.,Neuburger, Markus,Adjizian, Jean-Joseph,Ewels, Chris P.,Wegner, Hermann A.
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supporting information
p. 1594 - 1597
(2014/04/17)
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- Vasicine catalyzed direct C-H arylation of unactivated arenes: Organocatalytic application of an abundant alkaloid
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Vasicine, a quinazoline alkaloid isolated from Adhatoda vasica, has been employed as an organocatalyst for direct C-H arylation of unactivated arenes with aryl iodides/bromides without the assistance of any transition metal catalyst. A number of sensitive functional groups such as methyl, methoxy, O-benzyl, acetyl, and amino were well tolerated under present reaction conditions. Mechanistic investigation supported the involvement of radical intermediates.
- Sharma, Sushila,Kumar, Manoranjan,Kumar, Vishal,Kumar, Neeraj
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supporting information
p. 4868 - 4871
(2013/08/28)
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- The pyridyldiisopropylsilyl group: A masked functionality and directing group for monoselective ortho-Acyloxylation and ortho-Halogenation reactions of arenes
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A novel, easily removable and modifiable silicon-tethered pyridyldiisopropylsilyl directing group for C-H functionalizations of arenes has been developed. The installation of the pyridyldiisopropylsilyl group can efficiently be achieved via two complementary routes using easily available 2-(diisopropylsilyl)pyridine (5). The first strategy features a nucleophilic hydride substitution at the silicon atom in 5 with aryllithium reagents generated in situ from the corresponding aryl bromides or iodides. The second milder route exploits a highly efficient room-temperature rhodium(I)-catalyzed cross-coupling reaction between 5 and aryl iodides. The latter approach can be applied to the preparation of a wide range of pyridyldiisopropylsilyl- substituted arenes possessing a variety of functional groups, including those incompatible with organometallic reagents. The pyridyldiisopropylsilyl directing group allows for a highly efficient, regioselective palladium(II)-catalyzed mono-ortho-acyloxylation and ortho-halogenation of various aromatic compounds. Most importantly, the silicon-tethered directing group in both acyloxylated and halogenated products can easily be removed or efficiently converted into an array of other valuable functionalities. These transformations include protio-, deuterio-, halo-, boro-, and alkynyldesilylations, as well as a conversion of the directing group into the hydroxy functionality. In addition, the construction of aryl-aryl bonds via the Hiyama-Denmark cross-coupling reaction is feasible for the acetoxylated products. Moreover, the ortho-halogenated pyridyldiisopropylsilylarenes, bearing both nucleophilic pyridyldiisopropylsilyl and electrophilic aryl halide moieties, represent synthetically attractive 1,2-ambiphiles. A unique reactivity of these ambiphiles has been demonstrated in efficient syntheses of arylenediyne and benzosilole derivatives, as well as in a facile generation of benzyne. In addition, preliminary mechanistic studies of the acyloxylation and halogenation reactions have been performed. A trinuclear palladacycle intermediate has been isolated from a stoichiometric reaction between diisopropyl(phenyl)pyrid-2-ylsilane (3a) and palladium acetate. Furthermore, both C-H functionalization reactions exhibited equally high values of the intramolecular primary kinetic isotope effect (kH/k D=6.7). Based on these observations, a general mechanism involving the formation of a palladacycle via a C-H activation process as the rate-determining step has been proposed.
- Huang, Chunhui,Chernyak, Natalia,Dudnik, Alexander S.,Gevorgyan, Vladimir
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p. 1285 - 1305
(2011/07/07)
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- A general strategy toward aromatic 1,2-ambiphilic synthons: Palladium-catalyzed ortho-halogenation of PyDipSi-arenes
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A general and efficient strategy to synthesize 1,2-ambiphilic aromatic and heteroaromatic synthons from haloarenes has been developed. The method involves installation of the PyDipSi directing group, and subsequent palladium-catalyzed directed ortho-halogenation of aryl silanes (see scheme; Py=2-pyridyl). The usefulness of these 1,2-ambiphilic building blocks was shown in their participation as both nucleophilic aryl silane and electrophilic aryl iodide moieties.
- Dudnik, Alexander S.,Chernyak, Natalia,Huang, Chunhui,Gevorgyan, Vladimir
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supporting information; experimental part
p. 8729 - 8732
(2011/01/06)
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- Solid-phase synthesis with resin-bound triarylbismuthanes: Traceless and multidirectional cleavage of unsymmetrical biphenyls
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A multistep solid-phase organic synthesis with resin-bound bismuth linker is described. The flexibilities inherent in this system through novel chemoselective cross-coupling reactions, in conjunction with multidirectional and/or traceless cleavage methodologies, are exploited.
- Rasmussen, L. Kyhn,Begtrup, Mikael,Ruhland, Thomas
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p. 1230 - 1232
(2007/10/03)
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- Single and double Suzuki-Miyaura couplings with symmetric dihalobenzenes
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(Chemical Equation Presented) m- or p-diiodobenzene undergoes selective double coupling reactions with arylboronic acids and esters. Selectivity for double coupling over single coupling is remarkably strong: even with a diiodobenzene:monoboronic acid ratio of 10:1, the products of double coupling are formed in good yields. Steric hindrance and electronic influences of the boronic acid or ester, and reaction conditions do not appear to impact significantly upon the outcome of the reaction. In contrast, m- and p-dibromobenzenes undergo single couplings with aryl boronic acids with high selectivity.
- Sinclair, David J.,Sherburn, Michael S.
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p. 3730 - 3733
(2007/10/03)
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- Silicon directed ipso-substitution of polymer bound arylsilanes: Preparation of biaryls via the Suzuki cross-coupling reaction
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A method for attaching haloarylsilanes to polymer support was developed. The polymer bound arylhalide were reacted with a variety of ArB(OH)2 under the Suzuki cross-coupling reaction conditions and the coupled resins were cleaved by different electrophiles to give ipso-substitution products in good yields.
- Han, Yongxin,Walker, Shawn D.,Young, Robert N.
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p. 2703 - 2706
(2007/10/03)
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- Organic EL element and compound used therein
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Tetraaryldiamine derivatives of formula (1) are used in organic EL elements. R1, R2, R3, and R4 represent aryl, alkyl, alkoxy, aryloxy, amino or halogen, at least one of R1 to R4 is an aryl group, r1, r2, r3, and r4 are 0 or an integer of 1 to 5, the sum of r1 to r4 is at least 1, R5 and R6 represent alkyl, alkoxy, amino or halogen, r5 and r6 are 0 or an integer of 1 to 4. The inventive compounds have high m.p. and high Tg and can be evaporated to deposit transparent smooth thin films of quality which maintain a stable amorphous state above room temperature over a long term. Organic EL elements using the inventive compounds in an organic compound layer, typically a hole injecting and transporting layer thereof provide uniform plane light emission and maintain a high intensity of luminescence in a stable manner over a long term. Thus the elements are fully durable and reliable.
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- Photochemical reaction of onium salts with N,N-dimethylaniline: Evidence for photoinduced electron transfer
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Direct photolysis of diphenyliodonium salts gives significantly more iodobiphenyls than in the presence of dimethylaniline. An electron transfer reaction from the singlet excited state of dimethylaniline is proposed.
- Buijsen,Hacker
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p. 1557 - 1560
(2007/10/02)
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- Comparison of the Photochemistry of Diarylchloronium, Diarylbromonium, and Diaryliodonium Salts
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The direct and triplet-sensitized photochemistry of diphenylchloronium, diphenylbromonium, bis(4-methylphenyl)chloronium, and bis(4-methylphenyl)bromonium salts was studied.Direct photolysis of the diarylhalonium salts gave haloarene, 2-, 3-, and 4-halobiaryls, and acetanilide, predominantly from a heterolytic cleavage mechanism via the aryl cation-haloarene pair, via in-cage recombination and cage-escape reactions.However, triplet-sensitized photolysis gave haloarene, 2-, 3-, and 4-halobiaryl, and reduced arene mainly from homolytic cleavage to the arene radical-haloarene radical cation pair, which also gave in-cage recombination and cage-escape products.There is evidence for singlet-triplet interconversion of the excited states by spin-orbit coupling and interconversion of the singlet-triplet radical pairs by spin-spin coupling.In addition, electron transfer between the singlet arene cation-haloarene and arene radical-haloarene radical cation pairs is also possible.The effect of halogen and arene substituent on these interconversions is discussed.
- Dektar, John L.,Hacker, Nigel P.
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p. 1838 - 1844
(2007/10/02)
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- Photochemistry of Diaryliodonium Salts
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The photochemistry of diphenyl- and bis(4-methylphenyl)iodonium salts was investigated by product analysis, measurement of acid, and determination of the consumption of the iodonium salts.The primary products formed upon direct and triplet-sensitized irradiation of diphenyliodonium salts are iodobenzene, 2-, 3-, and 4-iodobiphenyl, acetanilide, benzene, and acid.Similarly, iodotoluene, iodobitolyls, 4-methylacetanilide, toluene, and acid are formed from photolysis of bis(4-methylphenyl)iodonium salts.The photolysis products are formed by heterolysis of the diaryliodonium salt to phenyl cation and iodobenzene and also by homolysis to phenyl radical and iodobenzene radical cation.Direct photolysis favors product formation by the heterolytic cleavage pathway, whereas triplet sensitization gives more product from homolytic cleavage.Interconversion between phenyl cation pair and the phenyl radical pair can occur by an electron transfer.Sensitized photodecomposition of the iodoniumsalts by anthracene gives iodoarene and arylated anthracenes by an electron-transfer mechanism.Electron-transfer quenching and triplet quenching by the iodonium salt are competitive reactions for some sensitizers.The similarities and differences between diaryliodonium and triarylsulfonium photochemistry will be described.
- Dektar, John L.,Hacker, Nigel P.
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p. 639 - 647
(2007/10/02)
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