- Catalytic Asymmetric Synthesis of Atropisomeric Quinolines through the Friedl?nder Reaction
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A phosphoric acid catalyzed atroposelective Friedl?nder reaction was developed in which acetylacetone and a variety of 2′-substituted 2-Aminobenzophenones were successfully employed to give optically active biaryl quinolines in good yields and with high enantioselectivities.
- Hu, Xingena,Jiang, Jun,Lan, Yunjun,Li, Juan,Li, Xinhua,Liu, Hongxin,Wan, Junlin,Xiao, Hong-Ping
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supporting information
p. 2198 - 2202
(2019/11/25)
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- Hydrodehalogenation of Haloarenes by a Sodium Hydride–Iodide Composite
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A simple protocol for hydrodebromination and -deiodination of halo(hetero)arenes was enabled by sodium hydride (NaH) in the presence of lithium iodide (LiI). Mechanistic studies showed that an unusual concerted nucleophilic aromatic substitution operates in the present process.
- Ong, Derek Yiren,Tejo, Ciputra,Xu, Kai,Hirao, Hajime,Chiba, Shunsuke
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supporting information
p. 1840 - 1844
(2017/02/05)
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- On the ionizing properties of supercritical carbon dioxide: Uncatalyzed electrophilic bromination of aromatics
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Supercritical carbon dioxide (scCO2), a solvent with a zero dipole moment, low dielectric constant, and no hydrogen bonding behavior, is a suitable medium to perform the uncatalyzed electrophilic bromination of weakly activated aromatics with no interference of radical pathways. The ability of scCO2 to promote these reactions matches those of strongly ionizing solvents such as aqueous acetic and trifluoroacetic acids. Conversely, carbon tetrachloride, with similar polarity parameters to scCO2, leads exclusively to side chain functionalization. The strong quadrupole moment, and the acidic, but non basic, Lewis character of carbon dioxide, are proposed as key factors for the singular performance of scCO2 in reactions involving highly polar and ionic intermediates.
- Delgado-Abad, Thais,Martnez-Ferrer, Jaime,Reig-Lpez, Javier,Mello, Rossella,Acerete, Rafael,Asensio, Gregorio,Gonzlez-Nez, Mara Elena
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p. 51016 - 51021
(2015/01/16)
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- Metal and H2O2 free aerobic oxidative aromatic halogenation with [RNH3+] [NO3-]/HX and [BMIM(SO3H)][NO3)x(X)y] (X = Br, Cl) as multifunctional ionic liquids
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Novel multifunctional ionic liquids (ILs) are generated by addition of HBr or HCl to alkylammonium nitrates ([RNH3+] [NO 3-]) and to 3-methyl-1-(butyl-4-sulfonyl)imidazolium nitrate ([BMIM(SO3H)][NO3]). The resulting [RNH 3+] [NO3-]/HX and mono (3-methyl-1-(butyl-4-sulfonyl)imidazolium) monohalogenide mononitrate ([BMIM(SO3H)][NO3)x(X)y] (X = Br, Cl)) systems act as solvent and promoter for aerobic oxidative halogenation of arenes under mild conditions in high yields that can be repeated over several cycles.
- Prebil, Rok,Laali, Kenneth K.,Stavber, Stojan
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supporting information
p. 2108 - 2111
(2013/06/05)
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- Bromination of alkylbenzenes in 1-butyl-3-methylimidazolium bromide and its dibromide complex
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Alkylbenzenes were subjected to bromination with molecular bromine using 1-butyl-3-methylimidazolium bromide as solvent. A complex of 1-butyl-3-methylimidazolium bromide with bromine was synthesized. It ensured bromination of alkylbenzenes with no bromine and solvent. The results of bromination in binary solvents and ionic liquids, 1-butyl-3-methylimidazolium bromide and tribromide were compared. The bromination of ethylbenzene with 1-butyl-3-methylimidazolium tribromide was accompanied by formation of a considerable amount of α-bromoethylbenzene, which is not typical of electrophilic aromatic substitution process.
- Gruzdev,Virzum,Krylov
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scheme or table
p. 263 - 267
(2010/08/06)
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- Erratum: Synthesis of functional phosphines with ortho-substituted aryl groups: 2-RC6H4PH2 and 2-RC6H 4P(SiMe3)2 (R = i -Pr- or t-Bu)
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The synthesis and characterization of 2-i-PrC6H 4PCl2 (3), 2-t-BuC6H4PCl2 (4), 2-i-PrC6H4PH2 (5), 2-t-BuC 6H4PH2 (6), 2-i-PrC6H 4P(SiMe3)2 (7), and 2-t-BuC6H 4P(SiMe3)2 (8) are described.
- Dugal-Tessier, Julien,Kuhn, Paul-Steffen,Dake, Gregory R.,Gates, Derek P.
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scheme or table
p. 355 - 360
(2011/04/22)
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- Process for Preparing Chloro-and Bromoaromatics
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The present invention relates to a novel process for preparing chloro- or bromoaromatics of the formula (II) by diazotizing the formula (I) by means of sodium nitrite or potassium nitrite in the presence of aqueous hydrochloric or hydrobromic acids and then reacting with an iron(II) or iron(III) compound, optionally in the presence of additional amounts of hydrogen chloride or hydrogen bromide or alkali metal or alkaline earth metal chlorides or bromides.
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Page/Page column 6
(2010/09/18)
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- Synthesis of functional phosphines with ortho-substituted aryl groups: 2-RC6H4PH2 and 2-RC6H 4P(SiMe3)2 (R = 2-/-Pr- or 2-f-Bu-)
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The synthesis and characterization of 2- i-PrC6H 4PCl2 (3), 2-t-BuC6H4PCl2 (4), 2-i-PrC6H4PH2 (5), 2-t-BuC 6H4PH2 (6), 2-i-PrC6H 4P(SiMe3)2 (7), and 2-t-BuC6H 4P(SiMe3)2 (8) are described.
- Dugal-Tessier, Julien,Kuhn, Paul-Steffan,Dake, Gregory R.,Gates, Derek P.
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scheme or table
p. 265 - 270
(2011/07/07)
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- Synthesis and structure of optically active 1,12-diethyl-and 1,12-diisopropylbenzo[c]phenanthrenes: An isopropyl group can be smaller than a methyl group
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1,12-Diethyl- and 1,12-diisopropylbenzo[c]phenanthrene-5,8-dicarboxylic acids were synthesized, and resolved. The dihedral angles formed by the A and D rings increased in the order of diisopropyl diethyl dimethyl as indicated by X-ray analysis, which showed that the strain decreased with the increase of the bulkiness at the 1,12-groups. Copyright
- Sugiura, Hiroki,Sakai, Daisuke,Otani, Harunori,Teranishi, Kazuhiro,Takahira, Yusuke,Amemiya, Ryo,Yamaguchi, Masahiko
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- Induced bromination of aromatic hydrocarbons with alkali metal bromides in the presence of oxidants
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The features of induced bromination of aromatic hydrocarbons in the NaBr(KBr)-HX-H2O2(NaOCl) system were studied. Pleiades Publishing, Inc., 2006.
- Sadygov,Alimardanov,Chalabiev
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p. 949 - 956
(2008/02/05)
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- A molecular mechanics approach to mapping the conformational space of diaryl and triarylphosphines
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A molecular mechanics force field has been developed which accurately reproduces experimental solid state structures and conformer interconversion barriers for a series of sterically congested diaryl and triaryl phosphines and some of their chalcogenide and Cr(CO)5 derivatives. The Royal Society of Chemistry 2006.
- Fey, Natalie,Howell, James A. S.,Lovatt, Jonathan D.,Yates, Paul C.,Cunningham, Desmond,McArdle, Patrick,Gottlieb, Hugo E.,Coles, Simon J.
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p. 5464 - 5475
(2007/10/03)
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- Induced bromination of aromatic hydrocarbons by alkali metals bromides and sodium hypochlorite
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Induced bromination of aromatic compounds in a system MBr-acid-NaOCl was studied. Optimum conditions of the process were developed, kinetics of the reactions were investigated, and the process mechanism was suggested. The bromination occurs both with the bromine in statu nascendi and with the hypobromous acid by hydrogen substitution exclusively in the aromatic ring. 2005 Pleiades Publishing, Inc.
- Sadygov,Alimardanov,Chalabiev
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p. 1631 - 1636
(2007/10/03)
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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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- Friedel-crafts alkylation and acylation in the absence of solvent
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A short and efficient synthetic route, for alkylation and acylation of aromatic compounds in the absence of solvent is developed. According to the reaction system and conditions used, different alkyl-, and acyl arenes are obtained in moderate to good yields. The structures are assigned by 1H and 13C NMR spectroscopy.
- Ghiaci,Asghari
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p. 2213 - 2220
(2007/10/03)
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- BROMINATION OF AROMATIC MOLECULES WITH POLYMER SUPPORTED REAGENTS
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Crosslinked co poly/styrene-4-vinyl(N-hexylpyridinium bromide) was converted with bromine or chlorine to insoluble polymer supported complexes 1 or 2 respectively, and their reactivity studied in reactions with various aromatic molecules.Reagent 1 was found in all cases to be milder than reagent 2 and regiospecifically transformed alkoxy and amino substituted benzenes (3) into 4-bromo derivatives, while corresponding reactions with 2 resulted in dibromo derivatives.Several benzoheterocyclic molecules were converted with 1 to substitution or addition products, i.e. 2,3-dibromo-N-methylpyrrole, 3-bromobenzo/b/thiophene, and 2,3-dibromo-2,3-dihydrobenzofuran.In the series of ortho-alkyl disubstituted benzene derivatives, i.e. o-xylene, indane, and tetraline, where the Mills-Nixon effect was established with various electrophilic reagents, bromination reactions with 2 showed higher β-selectivity than the corresponding reactions with bromine.The rate of bromination in various alkyl substituted benzenes with reagent 2 depended on the magnitude of the alkyl group, as well as the para/ortho regioselectivity, amounting to 100percent in the case of tert-butylbenzene.
- Zajc, Barbara,Zupan, Marko
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p. 7869 - 7878
(2007/10/02)
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- Bromination of alkylbenzenes in organic solvents. Substrate and position selectivity and effects of substituents
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The relative reactivity and the orientation of the entering group in the reaction of bromine with alkylbenzenes (C1-C4 alkyl groups, the last two with normal and iso structures) in organic solvents (acetic acid, acetic anhydride, nitromethane) under polythermal conditions (25-75 deg C) are determined mainly by the steric effects of the substituents.Nathan-Baker position and substrate effects are observed.Correlations close to linear are observed between the orientation (in the form of log 2P/O, where P and O are the relative amounts of the isomers in their reaction mixture) and the purely steric constants of the alkyl groups Es0.The substrate selectivity depends nonlinearly and inversely on Es0.The sensitivity of the orientation to change in the steric characteristics of the substituents shows an extremal dependence on the temperature with a maximum at about 50 deg C.
- Krylov, E. N.,Paramonova, O. K.
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p. 149 - 154
(2007/10/02)
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