24973-50-0Relevant articles and documents
Ligand-Promoted Direct C-H Arylation of Simple Arenes: Evidence for a Cooperative Bimetallic Mechanism
Kim, Jaewoon,Hong, Soon Hyeok
, p. 3336 - 3343 (2017/06/09)
A highly efficient catalyst for the direct C-H arylation of simple arenes was developed on the basis of a palladium-diimine complex. The developed catalyst exhibited the highest turnover number reported to date for the direct arylation of benzene due to increased stability provided by the diimine ligand. The reaction was also performed using only 2-3 equiv of simple arenes. Mechanistic studies in combination with kinetic measurements, isotope effect experiments, synthesis of possible intermediates, and stoichiometric reactions suggested that this reaction follows a cooperative bimetallic mechanism.
Transition-Metal-Free Cross-Coupling of Aryl Halides with Arylstannanes
He, Qing,Wang, Liwen,Liang, Yong,Zhang, Zunting,Wnuk, Stanislaw F.
, p. 9422 - 9427 (2016/10/17)
Transition-metal-free LiCl-promoted cross-coupling reactions of tetraphenyltin, trichlorophenyl-, dichlorodiphenyl-, and chlorotriphenylstannanes with aryl halides in DMF provided access to biaryls in good to high yields. Up to four phenyl groups were transferred from the organostannanes substrates. The aryls bearing electron-withdrawing groups in either halides or organotin substrates gave coupling products in higher yields. The methodology has been applied for the efficient synthesis of ipriflavones.
Palladium catalyzed cyanation of o-dichloroarenes with potassium hexacyanoferrate(ii)
Savicheva,Boyarskiy
, p. 980 - 983 (2013/07/25)
Cyanation of o-dichloroarenes with potassium hexacyanoferrate(ii) catalyzed by Pd(OAc)2/PPh3 system gave the corresponding phthalodinitriles in moderate yields. The method of competitive reactions revealed that activation rate of chl
The formation of dicyanoterphenyls by the interaction of terephthalonitrile dianion with biphenylcarbonitriles in liquid ammonia
Panteleeva, Elena V.,Bagryanskaya, Irina Yu.,Sal'Nikov, Georgij E.,Shteingartsa, Vitalij D.
, p. 123 - 133 (2011/06/23)
Terephthalonitrile dianion couples with biphenylcarbonitriles providing dicyanosubstituted m- and p-terphenyls. The influence of the cyano group position in biphenylcarbonitrile on the structure of the terphenyl scaffold is discussed. ARKAT USA, Inc.
Pd(PPh3)4-PEG 400 catalyzed protocol for the atom-efficient stille cross-coupling reaction of organotin with aryl bromides
Zhou, Wen-Jun,Wang, Ke-Hu,Wang, Jin-Xian
supporting information; experimental part, p. 5599 - 5602 (2009/12/03)
(Chemical Equation Presented) Aryl bromides (4 equiv) were coupled efficiently with organotin (1 equiv) in an atom-efficient way using the tetra(triphenylphosphine)palladium/polyethylene glycol 400 (Pd(PPh 3)4/PEG 400) catalytic syst
A new palladium catalyzed protocol for atom-efficient cross-coupling reactions of?triarylbismuths with aryl halides and triflates
Rao, Maddali L.N.,Jadhav, Deepak N.,Banerjee, Debasis
, p. 5762 - 5772 (2008/09/21)
A new palladium catalyzed protocol for an atom-efficient cross-coupling reaction of triarylbismuths with aryl halides and triflates has been described. The palladium catalytic system with Cs2CO3 base was found to be very efficient in DMA solvent to furnish excellent yields of cross-coupled functionalized biaryls in short reaction times.
Preparation of unsymmetrical biaryls via palladium-catalyzed coupling reaction of aryl halides
Hassan, Jwanro,Hathroubi, Chokri,Gozzi, Christel,Lemaire, Marc
, p. 7845 - 7855 (2007/10/03)
The synthesis of unsymmetrical biaryls is achieved using Pd(OAc)2 as the catalyst. A great variety of aryl halides having electron withdrawing and electron donating functional groups in para, meta and ortho positions have been successfully coupled.
THE PHOTOCHEMICAL NUCLEOPHILE-OLEFIN COMBINATION, AROMATIC SUBSTITUTION REACTION (PART 2): METHANOL-CYCLIC OLEFINS, 1,4-DICYANOBENZENE
Arnold, Donald R.,Snow, Miles S.
, p. 3012 - 3026 (2007/10/02)
Direct irradiation of acetonitrile-methanol (3:1) solutions of 1,4-dicyanobenzene and the cyclic olefins, cyclohexene, 1-methylcyclohexene, norbornene, and 2-methylnorbornene, leads to formation of regio- and stereoisomers of the 1:1:1 (alcohol : olefin : aromatic) adducts.This reaction can be photosensitized by electron transfer; addition of electron donors, biphenyl or phenanthrene, to the irradiation mixture generally increases the efficiency and yield of adduct formation.The efficiency of the reaction and the ratio of isomeric adducts are also affected by the addition of salts, particularly magnesium perchlorate.All of the possible regio- and stereoisomers from cyclohexene and 1-methylcyclohexene have been identified, two from cyclohexene and four from 1-methylcyclohexene.Three of the four possible isomers from norbornene were characterized; the endo, endo isomer was not detected.There are eight possible isomers from 2-methylnorbornene; six were detected and five have been isolated and identified.The two sterically hindered isomers, those having both the 4-cyanophenyl and the methoxy groups in the endo position, and exo-3-(4-cyanophenyl)-endo-2-methoxy-exo-2-methylnorbornane, were not characterized.The structures of the products were established largely on the basis of the 1H and 13C nuclear magnetic resonance spectra.The mechanism of the reaction is discussed, with emphasis on those factors that may affect the product ratio.The most striking observation is that the reaction is regioselective when magnesium perchlorate is added to the irradiation mixture.
Vapour-phase Chemistry of Arenes. Part 13. Reactivity and Selectivity in the Gas-phase Reactions of Hydroxyl Radicals with Monosubstituted Benzenes at 563 K
Mulder, Peter,Louw, Robert
, p. 1167 - 1174 (2007/10/02)
The reactions of hydroxyl radicals with benzene derivates C6H5Z (Z = H, Me, F, Cl, Br, I, CF3, or CN) have been studied in a flow reactor at 563 K in nitrogen, using the thermolysis of ButOOH as a source of .OH.Under these conditions there are two product-forming pathways.The major one involves hydrogen abstraction to give aryl radicals ZC6H4. (II) as the first step; depending on Z, its displacement to form phenol may also occur.Relative rates for hydrogen abstraction were determined in competition experiments using side-chain hydrogen abstraction from added toluene as a reference.This resulted in the order (for Z =): 1,8(Me), 1.0(H), 0.47(F), 0.29(Cl), 0.34(CF3), 0.20(CN), consonant with the electrophilic nature of .OH.The site selectivity of hydrogen abstractions was determined by scavenging part of the aryl radicals (II) with iodine.A Hammett plot, using ? constants for meta and para positions, led to ρ -1.0.The features of hydrogen abstraction by .OH are discussed and compared with those for the analogous reaction of Cl.The formation of phenol was found to decrease in importance in the order F, Cl, Br, and I.This result is rationalized on a thermochemical kinetic basis.
Phase-Transfer-Catalyzed Gomberg-Bachmann Synthesis of Unsymmetrical Biarenes: A Survey of Catalysts and Substrates
Beadle, James R.,Korzeniowsky, Stephen H.,Rosenberg, David E.,Garcia-Slanga, Blanche J.,Gokel, George W.
, p. 1594 - 1603 (2007/10/02)
Two problems have hindered the Gomberg-Bachmann (GB) and Pschorr reactions of arenediazonium cations: the instability of the arenediazonium salts and side reactions.Arenediazonium tetrafluoroborate and hexafluorophosphate salts can be prepared in high yield and purity and can be stored safely.Unfortunately, these salts are insoluble in most nonpolar organic solvents.Crown ether complexation or other phase-transfer (pt) catalytic methodology can ameliorate this situation, and reactions conducted by the approaches outlined herein often afforded coupling or cyclization products in high yield and corresponding purity.The use of crown ethers, quarternary 'onium salts, lipophilic carboxylic acid salts, and even the polar cosolvent acetonitrile increase the utility of the ptGB reaction dramatically.Sixty examples of couplings are reported along with an assessment of selectivities.A number of examples are also presented of phase-transfer-type Pschorr cyclizations.In the latter case, the use of potassium superoxide, KO2, is introduced to suppress indazole formation.
