- Alumina-Mediated π-Activation of Alkynes
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The ability to induce powerful atom-economic transformation of alkynes is the key feature of carbophilic π-Lewis acids such as gold- and platinum-based catalysts. The unique catalytic activity of these compounds in electrophilic activations of alkynes is explained through relativistic effects, enabling efficient orbital overlapping with π-systems. For this reason, it is believed that noble metals are indispensable components in the catalysis of such reactions. In this study, we report that thermally activated γ-Al2O3activates enynes, diynes, and arene-ynes in a manner enabling reactions that were typically assigned to the softest π-Lewis acids, while some were known to be triggered exclusively by gold catalysts. We demonstrate the scope of these transformations and suggest a qualitative explanation of this phenomenon based on the Dewar-Chatt-Duncanson model confirmed by density functional theory calculations.
- Akhmetov, Vladimir,Amsharov, Konstantin,Feofanov, Mikhail,Sharapa, Dmitry I.
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p. 15420 - 15426
(2021/09/30)
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- Construction of Phenanthrenes and Chrysenes from β-Bromovinylarenes via Aryne Diels-Alder Reaction/Aromatization
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A highly efficient transition-metal-free general method for the synthesis of polycyclic aromatic hydrocarbons like phenanthrenes and chrysenes (and tetraphene) from β-bromovinylarenes and arynes has been developed. The reactions proceed via an aryne Diels-Alder (ADA) reaction, followed by a facile aromatization. This is the first report on direct construction of chrysenes (and tetraphene) using the ADA approach. Unlike the literature method which is limited to only 9/10-substituted derivatives, this method gives access to a wide variety of functionalized phenanthrenes.
- Singh, Vikram,Verma, Ram Subhawan,Khatana, Anil K.,Tiwari, Bhoopendra
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p. 14161 - 14167
(2019/10/28)
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- Oxidative, Iodoarene-Catalyzed Intramolecular Alkene Arylation for the Synthesis of Polycyclic Aromatic Hydrocarbons
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A catalytic, metal-free and chemoselective oxidative intramolecular coupling of arene and alkene C?H bonds is reported. The active hypervalent iodine (HVI) reagent, generated catalytically in situ from iodotoluene and meta-chloroperoxybenzoic acid (m-CPBA), reacts with o-vinylbiphenyls to generate polyaromatic hydrocarbons in up to 95 % yield. Experimental evidence suggests the reactions proceed though vinyliodonium and, possibly, vinylenephenonium intermediates.
- Zhao, Zhensheng,Britt, Liam H.,Murphy, Graham K.
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p. 17002 - 17005
(2018/11/01)
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- Further insight into the photochemical behavior of 3-aryl-N-(arylsulfonyl)propiolamides: tunable synthetic route to phenanthrenes
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Reported herein is further insight into the photochemical behaviour of 3-aryl-N-(arylsulfonyl)-propiolamides, which provides a straightforward way to access meaningful phenanthrenes. Mechanistic investigation indicated that aryl migration, C-C coupling, 1,3-hydrogen shift, desulfonylation and elimination were involved in the process. Moreover, this protocol allowed for scale-up using a flow reactor.
- Chen, Ming,Zhao, Xinxin,Yang, Chao,Wang, Yanpei,Xia, Wujiong
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p. 12022 - 12026
(2017/03/01)
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- Facile Synthesis of Polycyclic Aromatic Hydrocarbons: Br?nsted Acid Catalyzed Dehydrative Cycloaromatization of Carbonyl Compounds in 1,1,1,3,3,3-Hexafluoropropan-2-ol
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The cycloaromatization of aromatic aldehydes and ketones was readily achieved by using a Br?nsted acid catalyst in 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP). In the presence of a catalytic amount of trifluoromethanesulfonic acid, biaryl-2-ylacetaldehydes and 2-benzylbenzaldehydes underwent sequential intramolecular cationic cyclization and dehydration to afford phenacenes and acenes, respectively. Furthermore, biaryl-2-ylacetaldehydes bearing a cyclopentene moiety at the α-position underwent unprecedented cycloaromatization including ring expansion to afford triphenylenes. HFIP effectively promoted the cyclizations by suppressing side reactions presumably as a result of stabilization of the cationic intermediates.
- Fujita, Takeshi,Takahashi, Ikko,Hayashi, Masaki,Wang, Jingchen,Fuchibe, Kohei,Ichikawa, Junji
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p. 262 - 265
(2017/01/24)
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- Polycationic ligands in gold catalysis: Synthesis and applications of extremely π-acidic catalysts
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Very often ligands are anionic or neutral species. Cationic ones are rare, and, when used, the positively charged groups are normally appended to the periphery of the ligand. Here, we describe a dicationic phosphine with no spacer between the phosphorus atom and the two positively charged groups. This structural feature makes its donor ability poorer than that of phosphites and only comparable to extremely toxic or pyrophoric compounds such as PF 3 or P(CF3)3. By exploiting these properties, a new Au catalyst has been developed displaying a dramatically enhanced capacity to activate π-systems. This has been used to synthesize very sterically hindered and naturally occurring 4,5-disubstituted phenanthrenes. The present approach is expected to be applicable to the development and improvement of many other transition metal catalyzed transformations that benefit from extremely strong π-acceptor ligands. The mechanism of selected catalytic transformations has been explored by density functional calculations.
- Carreras, Javier,Gopakumar, Gopinadhanpillai,Gu, Liangu,Gimeno, Ana,Linowski, Pawel,Petu?kova, Jekaterina,Thiel, Walter,Alcarazo, Manuel
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p. 18815 - 18823
(2014/01/06)
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- Synthesis of phenanthrenes by cationic chromium(III) porphyrin-catalyzed dehydration cycloaromatization
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Readily available biphenyl derivatives with ortho oxirane moiety react in the presence of cationic chromiun(III) porphyrin catalyst to afford phenanthrenes. The reaction is considered to be triggered by activation of the oxirane moiety through coordination to the Lewis acidic cationic chromium to give aldehyde via 1,2-hydride shift, which reacts with arene through intramolecular electrophilic aromatic substitution and subsequent dehydration. The reaction allows constructing a variety of polycyclic aromatic and heteroaromatic compounds.
- Wakabayashi, Ryota,Kurahashi, Takuya,Matsubara, Seijiro
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supporting information
p. 2297 - 2301
(2013/11/06)
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- Straightforward synthesis of phenanthrenes from styrenes and arenes
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Semi-one-pot synthesis of phenanthrenes from styrenes and arenes was developed through cross-dehydrogenative coupling. A sequence of Heck-type coupling and photo-cyclization were involved and a variety of functionalities were tolerated. This method provides an effective and practical protocol towards the synthesis of substituted phenanthrenes. The Royal Society of Chemistry 2012.
- Li, Hu,He, Ke-Han,Liu, Jia,Wang, Bi-Qin,Zhao, Ke-Qing,Hu, Ping,Shi, Zhang-Jie
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supporting information; experimental part
p. 7028 - 7030
(2012/08/07)
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- Synthesis of phenanthrene and alkyl phenanthrenes by palladium(0)-catalyzed pericyclic reactions
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Palladium-catalyzed pericyclic reactions have been developed for the synthesis of phenanthrenes. This method is also useful for the synthesis of monoalkyl and dialkyl phenanthrene derivatives. Georg Thieme Verlag Stuttgart.
- Jana, Rathin,Biswas, Anup,Samanta, Shubhankar,Ray, Jayanta K.
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scheme or table
p. 2092 - 2100
(2010/08/20)
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- Studies towards the total synthesis of Sch 56036; isoquinolinone synthesis and the synthesis of phenanthrenes
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The isoquinolinone hemisphere of Sch 56036 has been prepared using a modified Pomeranz-Fritsch reaction and the synthesis of the phenanthrene core has been modelled via a Suzuki coupling and subsequent ring closing metathesis.
- Walker, Edward R.,Leung, Shing Y.,Barrett, Anthony G.M.
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p. 6537 - 6540
(2007/10/03)
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- Evaluation of acute toxicity and genotoxicity of liquid products from pyrolysis of Eucalyptus grandis wood
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Slow pyrolysis of Eucalyptus grandis wood was performed in an oven laboratory, and smoke was trapped and condensed to yield liquid products. Polycyclic aromatic hydrocarbons (PAHs) and phenolic fractions were isolated from the former liquid products using adsorption column chromatography (ACC) and identified by GC/MS. Concentrations of PAH and phenolic fractions in total pyrolysis liquids were respectively 48.9 μg/g and 8.59% (w/w). Acute toxicity of total samples of pyrolysis liquids and the phenolic fraction was evaluated by means of two bioassays, namely, 24-h immobilization bioassay with Daphnia magna and Microtox(TM) bioassays, the latter employing the luminescent bacteria Photobacterium phosphoreum. Total pyrolysis liquids and the PAH fraction were evaluated for genotoxicity by the Microtox(TM) bioassay conducted using rehydrated freeze-dried dark mutant of the luminescent bacteria Vibrio fisheri strain M169. Total pyrolysis liquids and the phenolic fraction, respectively, in concentrations of 170 and 68 mg/L were able to immobilize 50% (EC50) of the D. magna population following 24-h exposure. Concentrations of 19 and 6 mg/L, respectively, for total pyrolysis liquids and phenolic fraction were the effective concentrations that resulted in a 50% (EC50) reduction in light produced by bacteria in the Microtox(TM) bioassay. Accordingly, the Microtox(TM) bioassay was more sensitive to toxic effects of both kind of samples than the D. magna bioassay, particularly for the phenolic fraction. Regarding to the genotoxicity evaluation, the results achieved by Microtox(TM) bioassay showed that total pyrolysis liquids had no genotoxic effects with and without exogenous metabolic activation using rat liver homogenate (S9). However, the PAH fraction showed toxic effects with rat liver activation and had a dose-response number (DRN) equal to 1.6, being in this way suspected genotoxic. The lowest detected concentration (LDC) of the PAH fraction able to cause genotoxic effects was 375 μg/L.
- Pimenta,Bayona,Garcia,Solanas
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p. 169 - 175
(2007/10/03)
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- Photochemistry of Stilbenes. 8. Eliminative Photocyclization of o-Methoxystilbenes
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The synthetic value of the eliminative photocyclization of o-methoxystilbenes to give phenanthrenes with loss of the element of methanol has been enhanced by the use of tert-butyl alcohol as the solvent and sulfuric acid as a catalyst. 2-Methoxy-5-X-stilbenes and 2-methoxy-3-X-stilbenes undergo this photoreaction to produce the corresponding 2-X-phenanthrenes and 4-X-phenanthrenes, respectively.This regioselective photochemical route to these particular types of substituted phenanthrenes represents an improvement synthetically over the well-known oxidative photocyclization method with meta-substituted stilbenes, from which approximately 1:1 mixtures of 2-substituted and 4-substituted phenanthrenes usually are obtained.An attempt to extend the scope of this eliminative photocyclization method to the synthesis of benzanthracene by the ultraviolet irradiation of 3-methoxy-2-styrylnaphthalene was not successful, but this synthetic objective was achieved in an alternative way by the eliminative photocyclization of 5,6,7,8-tetrahydro-3-methoxy-2-styrylnaphthalene followed by oxidation of the resulting 8,9,10,11-tetrahydrobenzanthracene with DDQ.
- Mallory, Frank B.,Rudolph, M. Jonathan,Oh, Soon M.
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p. 4619 - 4626
(2007/10/02)
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- The thermodynamic properties of 4-methylphenanthrene
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Measurements leading to the calculation of the ideal-gas thermodynamic properties for 4-methylphenanthrene are reported.Thermochemical and thermophysical properties were determined by adiabatic heat-capacity calorimetry, combustion calorimetry, comparative ebulliometry, and inclined-piston manometry.Results were used to calculate entropies, enthalpies, and Gibbs energies of formation for the ideal-gas state at selected temperatures to 500 K.Group-contribution methods involving comparisons for a series of methyl-substituted aromatic molecules were used to demonstrate the consistency of ideal-gas entropies and the enthalpy of formation determined for 4-methylphenanthrene with literature values for related compounds.The results are shown to be in accord with a barrier to methyl rotation from the literature determined using n.m.r. spectroscopy.
- Chirico, R. D.,Hossenlopp, I. A.,Nguyen, A.,Steele, W. V.,Gammon, B. E.
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p. 179 - 202
(2007/10/02)
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- Photocyclization of o-Halostilbenes
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The photocyclization reactions of several ortho-halogenated stilbene derivatives were examined under both oxidative conditions (iodine/cyclohexane) and basic conditions (sodium methoxide/methanol).The major products were those anticipated from photodehydrogenation and photodehydrohalogenation, respectively.In some cases photodebromination of the product occurred.Some regiochemical control in phenanthrene synthesis can be achieved as is illustrated by a synthesis of dehydroorchinol acetate.
- Olsen, Robert J.,Pruett, Stephen R.
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p. 5457 - 5460
(2007/10/02)
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- Electrophilic Substitution in Naphthalenes: Cyclisation of Naphthylbutanols to Tetrahydrophenanthrene
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Both 4-(1-naphthyl)butanol and 4-(2-naphthyl)butanol cyclised in refluxing boron trifluoride-ether to give 1,2,3,4-tetrahydrophenanthrene.By use of the corresponding 1,1-dideuteriobutanol derivatives and analysis of the products by 220 MHz 1H n.m.r. spectroscopy it has been demonstrated that the 1-naphthylbutanol cyclises by two distinct pathways, (a) by direct attack (84percent) at the 2-position, and (b) by ipso-attack (16percent) at the 1-position of the naphthalene nucleus, followed by rearrangement.The 2-naphthylbutanol cyclises exclusively by direct substitution at the 1-position.With 4-(4-methoxy-1-naphthyl)-1,1-dideuteriobutanol on the other hand the proportion of ipso-substitution rises to 71 percent as shown by the 360 MHz 1H n.m.r. spectra of the resulting mixture of tetrahydrophenanthrenes.
- Jackson, Anthony H.,Shannon, Patrick V. R.,Taylor, Paul W.
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p. 286 - 297
(2007/10/02)
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- The formation and reactions of 9,10-phenanthryne and related arynes by pyrolytic reactions in the vapor phase
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The formation of 9,10-phenanthryne (5), 4-methyl-9,10-phenanthryne (7) and 9,10-benz(c)phenanthryne (9) by the thermal degradation of appropriate arenedicarboxylic acid anhydrides has been investigated by a combination of VLPP and mass spectrometry and by a co-pyrolysis of the anhydrides with benzene, hexadeuterobenzene and 1,3-butadiene. Compounds 5,7 and especially 9 are formed easily by VLPP at 700-900° from the anhydrides. The results indicate that 7 and 9 are less reactive by H-addition to the aryne bond than 5, benzyne or naphthalyne, respectively. The results of the co-pyrolysis experiments show that 5 and 9 react with benzene and 1,3-butadiene by H-abstraction and addition reactions, similar to 1,2-benzyne and 2,3-naphthalyne. However, the reactivity of the aryne in the H-abstraction reaction decreases and the selectivity for the addition reaction increases in the series 1,2-benzyne, 2,3-naphthalyne, 9,10-phenanthryne and 9,10benz(c)phenanthryne.
- Gruetzmacher, Hans-Fr.,Strabtmans, Udo
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p. 807 - 813
(2007/10/02)
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