- Biaryl Coupling of Aryldiazonium Salts and Arylboronic Acids Catalysed by Gold
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A gold-catalysed coupling of aryldiazonium salts with arylboronic acids is described. The reactions proceed in satisfactory yields under irradiation with blue LEDs in the presence of KF and a catalytic amount of ascorbic acid. Notably, 4-nitrobenzendiazonium tetrafluoroborate is sufficiently reactive to undergo the coupling with a variety of arylboronic acids in the absence of aryl radical initiators. The coupling is applicable for electron-donating and electron-withdrawing groups present at the para, ortho, and meta positions of both substrates.
- Medina-Mercado, Ignacio,Porcel, Susana
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- Azo bond formation on metal surfaces
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The formation of azo compounds via redox cross-coupling of nitroarenes and arylamines, challenging in solution phase chemistry, is achieved by on-surface chemistry. Reaction products are analyzed with a cryogenic scanning tunneling microscope (STM) and X-ray photoelectron spectroscopy (XPS). By using well-designed precursors containing both an amino and a nitro functionality, azo polymers are prepared on surface via highly efficient nitro-amino cross-coupling. Experiments conducted on other substrates and surface orientations reveal that the metal surface has a significant effect on the reaction efficiency. The reaction was further found to proceed from partially oxidized/reduced precursors in dimerization reactions, shedding light on the mechanism that was studied by DFT calculations.
- Meng, Xiangzhi,Klaasen, Henning,Viergutz, Lena,Schulze Lammers, Bertram,Witteler, Melanie C.,M?nig, Harry,Amirjalayer, Saeed,Liu, Lacheng,Neugebauer, Johannes,Gao, Hong-Ying,Studer, Armido,Fuchs, Harald
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supporting information
p. 1458 - 1464
(2020/12/14)
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- Copper catalysed Gomberg-Bachmann-Hey reactions of arenediazonium tetrafluoroborates and heteroarenediazonium o-benzenedisulfonimides. Synthetic and mechanistic aspects
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Gomberg-Bachmann-Hey reactions were carried out in the presence of copper as a catalyst and gave rise to biaryls or heterobiaryls in good yields and in mild reaction conditions. A computational study of some key points of the reaction was performed. The results are coherent with the experimental data and confirm some aspects of the mechanism. The reaction free energies for the reduction in benzene by CuI of a set of 40 (hetero)arenediazonium tetrafluoroborates were calculated. Both the experiments and the calculations showed that in the coupling with substituted solvents (toluene, bromobenzene, nitrobenzene and anisole) the binding to the ortho position was always favoured.
- Antenucci, Achille,Barbero, Margherita,Dughera, Stefano,Ghigo, Giovanni
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- Modular and Selective Arylation of Aryl Germanes (C?GeEt3) over C?Bpin, C?SiR3 and Halogens Enabled by Light-Activated Gold Catalysis
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Selective C (Formula presented.) –C (Formula presented.) couplings are powerful strategies for the rapid and programmable construction of bi- or multiaryls. To this end, the next frontier of synthetic modularity will likely arise from harnessing the coupling space that is orthogonal to the powerful Pd-catalyzed coupling regime. This report details the realization of this concept and presents the fully selective arylation of aryl germanes (which are inert under Pd0/PdII catalysis) in the presence of the valuable functionalities C?BPin, C?SiMe3, C?I, C?Br, C?Cl, which in turn offer versatile opportunities for diversification. The protocol makes use of visible light activation combined with gold catalysis, which facilitates the selective coupling of C?Ge with aryl diazonium salts. Contrary to previous light-/gold-catalyzed couplings of Ar–N2+, which were specialized in Ar–N2+ scope, we present conditions to efficiently couple electron-rich, electron-poor, heterocyclic and sterically hindered aryl diazonium salts. Our computational data suggest that while electron-poor Ar–N2+ salts are readily activated by gold under blue-light irradiation, there is a competing dissociative deactivation pathway for excited electron-rich Ar–N2+, which requires an alternative photo-redox approach to enable productive couplings.
- Dahiya, Amit,Fricke, Christoph,Funes-Ardoiz, Ignacio,Gevondian, Avetik G.,Schoenebeck, Franziska,Sherborne, Grant J.
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supporting information
p. 15543 - 15548
(2020/06/22)
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- Synthesis, characterization and catalytic performance of palladium supported on pyridine-based covalent organic polymer for Suzuki-Miyaura reaction
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A bipyridine-based covalent organic polymer (COP) was successfully synthesized by condensation of trimesoyl chloride (TMC) and 2,2′-bipyridine-5,5′-diamine (Bpy) under ambient conditions. This material was modified by coordination of PdCl2 to COP framework, affording a hybrid material, Pd@TMC-Bpy COP, which was applied as a highly efficient heterogeneous catalyst for Suzuki-Miyaura reaction under ligand-free conditions in ethyl lactate. The catalyst could be reused for five times without obvious loss of its activity.
- Han, Yi,Di, Jia-Qi,Zhao, Ai-Dong,Zhang, Zhan-Hui
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- Gold catalysed Suzuki-Miyaura coupling of arenediazonium o-benzenedisulfonimides
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Arenediazonium o-benzenedisulfonimides have been used as efficient electrophilic partners in Au(I) catalysed Suzuki coupling reactions. The synthetic protocol is general, easy and produced either biaryls or heteroaryl arenes in good yields (51 positive examples, average yield 80%). o-Benzenedisulfonimide was recovered at the end of the reactions and was reused to prepare the starting salts for further reactions. Mechanistic insights suggest that the o-benzenedisulfonimide anion act as an electron transfer agent and promotes a catalytic cycle which does not require the presence of photocatalysts or external oxidants.
- Barbero, Margherita,Dughera, Stefano
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p. 5758 - 5769
(2018/09/10)
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- Ni(II) catalyzed bromination of aryl C-H bonds
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Bromination of unactivated aromatic C-H bonds without directing and/or chelating groups was achieved by employing an air stable N-heterocyclic Ni(II) complex. PhI(OAC)2 and N-bromosuccinimide have been used as the oxidizing agent and the bromin
- Bhattacharya, Moumita,Cluff, David B.,Das, Siddhartha
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p. 238 - 241
(2014/12/11)
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- Ni(II) catalyzed bromination of aryl C-H bonds
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Bromination of unactivated aromatic C-H bonds without directing and/or chelating groups was achieved by employing an air stable N-heterocyclic Ni(II) complex. PhI(OAC)2and N-bromosuccinimide have been used as the oxidizing agent and the bromine source, respectively. Yields for bromination are as high as >99%, especially in presence of electron-withdrawing groups like -NO2and -CF3. This is a rare report on C-H bond activation with Ni(II) where, instead of homo C-C coupling, reductive elimination to form C-halogen could be achieved.
- Bhattacharya, Moumita,Cluff, David B.,Das, Siddhartha
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p. 238 - 241
(2015/02/20)
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- Selective Suzuki-Miyaura monocouplings with symmetrical dibromoarenes and aryl ditriflates for the one-pot synthesis of unsymmetrical triaryls
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The various parameters that would permit selective Suzuki-Miyaura monocouplings of symmetrical dihaloarenes were studied. High selectivity and efficiency can be obtained for a broad range of substrates by using operationally simple conditions and widely available reagents. The 38 different examples described provide a valuable toolbox for the rapid access to unsymmetrical triaryls, as illustrated by the preparation of diarylpyridine 8, terphenyl 9, and diarylpyrrole 10. By studying several key parameters, the factors that allow selective Suzuki-Miyaura monocoupling of symmetrical dihaloarenes have been outlined. This study serves as the basis for the efficient synthesis of unsymmetrical triaryls from symmetrical dibromoarenes and aryl ditriflates by a one-pot desymmetrizing double Suzuki-Miyaura coupling. Copyright
- Minard, Corinne,Palacio, Carole,Cariou, Kevin,Dodd, Robert H.
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p. 2942 - 2955
(2014/05/20)
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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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- Syntheses and crystal structures of ferrocenyl derivatives of biphenyl
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Arylation of ferrocene with substituted biphenyldiazonium tetrafluoroborates afforded 4-bromo-, 4-nitro-, and 4-cyano-4′- ferrocenylbiphenyls. 4-Nitro- and 4-cyano-4′-ferrocenylbiphenyls were studied by X-ray diffraction analysis. In the crystals of 4-nitro-4′- ferrocenylbiphenyl, the molecules are linked via stacking π-π interactions.
- Lemenovskii,Makarov,Dyadchenko,Bruce,Bruce,Larkin,Averkiev,Starikova,Antipin
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p. 607 - 615
(2007/10/03)
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- Diamine hole transport agent and organic electroluminescent device containing same
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A novel diamine compound of formula (I) of the present invention having a high glass transition temperature is useful as an improved hole transport agent, and an organic electroluminescent device containing the diamine compound of formula (I) has good thermal and mechanical stabilities, and prolonged lifetime.
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- Diamine hole transport agent and organic electroluminescent device containing same
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A novel diamine compound of formula (I) of the present invention having a high glass transition temperature is useful as an improved hole transport agent, and an organic electroluminescent device containing the diamine compound of formula (I) has good thermal and mechanical stabilities, and prolonged lifetime.
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- Process for preparing nitrobiphenylene
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The invention concerns a process for preparing nitrobiphenylene of formula (I) wherein m stands for 1 or 2, R means halogen, R' or OR', R' being a C-organic group which can carry groups which are inert in the reaction conditions, n stands for 0, 1, 2 or 3 and, if n is 2 or 3, the R groups can also be different. According to the invention, a chloronitrobenzene of formula (II) is reacted in the presence of a palladium catalyst and a base in a solvent with a phenyl boric acid (IIIa), one of its alkyl esters of formula (IIIb), R meaning C1-C6 alkyl, or one of its anhydrides. The compounds (I) are suitable as initial products for biphenylamines which are in turn intermediate products for fungicidal plant-growth substances.
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- Organometallic complexes for nonlinear optics. X. 1 Molecular quadratic and cubic hyperpolarizabilities of systematically varied (cyclopentadienyl) bis(phosphine) ruthenium σ-arylacetylides
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The complexes Ru(4,4′-C ≡ CC6H4C6H4NO2)(PPh3)2(η-C5H5) and Ru(4,4′-C ≡ CC6H4C ≡ CC6H4NO2)(PPh3)2(η-C5H5) have been prepared and the latter structurally characterized; they belong to a series of organometallic donor-bridge-acceptor compounds containing (cyclopentadienyl)bis(phosphine)ruthenium(II) centres as donors, conjugated arylacetylide bridges, and nitro acceptor groups. Electrochemical data for the series of complexes Ru(C ≡ CR)(PR′3)2(η-C5H5) (R=Ph, 4-C6H4NO2, R′=Ph, Me; R=4,4′-C6H4C6H4NO2, (E)-4,4′-C6H4CH=CHC6H4NO2, 4,4′-C6H4C ≡ CC6H4NO2, 4,4′-C6H4N=CHC6H4NO2, R′=Ph) are consistent with an RuII/III couple whose oxidation potentials vary strongly with chain-lengthening from one-ring to two-ring acetylide ligand, but show little variation with changes at the bridging unit of the two-ring acetylide ligand. The molecular quadratic and cubic optical nonlinearities of the series of complexes have been determined by hyper-Rayleigh scattering (HRS) and Z-scan techniques, respectively. Molecular first hyperpolarizabilities by HRS at 1064 nm are dispersively enhanced; experimental and two-level corrected data suggest an increase in nonlinearity on chain-lengthening of the bridge, in proceeding from C6H4 to C6H4C6H4 and then C6H4C ≡ CC6H4 and C6H4CH=CHC6H4, a general trend that is reproduced by semiempirical ZINDO computations. Cubic hyperpolarizabilities by Z-scan at 800 nm are negative for complexes with nitro acceptor groups, probably a result of two-photon dispersion, with absolute values (up to 850 × 10-36 esu) large for small organometallic complexes; as with quadratic nonlinearities, cubic nonlinearities increase substantially on bridge lengthening, with little variation on phosphine substitution.
- Whittall, Ian R.,Cifuentes, Marie P.,Humphrey, Mark G.,Luther-Davies, Barry,Samoc, Marek,Houbrechts, Stephan,Persoons, Andre,Heath, Graham A.,Hockless, David C. R.
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p. 127 - 137
(2007/10/03)
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