- Triple Benzannulation of Naphthalene via a 1,3,6-Naphthotriyne Synthetic Equivalent. Synthesis of Dibenz[a,c]anthracene
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A new synthesis of dibenzo[a,c]anthracene (4) is described that features the generation, from tetrabromo-bis-triflate 1 and phenyllithium, of a 1,3,6-naphthotriyne (2) synthetic equivalent that is trapped with 3 equiv of furan to form Diels-Alder tris-adduct 3. A subsequent two-step deoxygenation of 3 represents the first synthesis of dibenz[a,c]anthracene (4) that involves a tandem aryne Diels-Alder cycloaddition-deoxygenation strategy.
- Mannes, Philip Z.,Onyango, Evans O.,Gribble, Gordon W.
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- Palladium Catalyzed C-I and Vicinal C-H Dual Activation of Diaryliodonium Salts for Diarylations: Synthesis of Triphenylenes
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Using the synthetic strategy of palladium-catalyzed dual activation of both C-I and vicinal C-H bonds of diaryliodonium salts, we report an approach for direct diarylations of 2-bromobiphenyls or bromobenzenes. As a result, a wide range of triphenylenes with various substituents have been synthesized in good yields. These triphenylenes are expected to be employed in the "bottom-up" synthesis of functional aromatic molecules in material science.
- Wu, Xunshen,Han, Jianwei,Wang, Limin
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- Synthesis and characterization of oxadisilole fused benzo[b]triphenylene
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Palladium-catalyzed [2+2+2] cyclotrimerization reactions between benzyne and oxadisilole fused oxabicyclic alkenes afforded the exo-adducts. Deoxygenation with BF3·OMe2 yielded mono- and bis-oxadisilole fused benzo[b]triphenylene. The photophysical properties of the oxadisilole fused benzo[b]triphenylenes were characterized.
- Chen, Ya-Li,Wong, Man-Shing,Wong, Wai-Yeung,Lee, Albert W.M.
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- Palladium-catalyzed [2 + 2 + 2] cocyclotrimerization of benzynes with bicyclic alkenes: An efficient route to anellated 9,10-dihydrophenanthrene derivatives and polyaromatic compounds
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An efficient method for the cocyclotrimerization of bicyclic alkenes and benzynes catalyzed by palladium phosphine complexes to give the corresponding norbornane anellated 9,10-dihydrophenanthrene derivatives is described. Bicyclic alkenes 1a-i undergo [2 + 2 + 2] cocyclotrimerization with benzynes generated from precursors 2a-d [2-(trimethylsilyl)phenyl triflate (2a), 4,5-dimethyl-2-(trimethylsilyl)phenyl triflate (2b), 6-(trimethylsilyl)-2,3- dihydro-1H-5-indenyl triflate (2c), 4-methyl-2-(trimethylsilyl)phenyl triflate (2d)] in the presence of PdCl2(PPh3)2 in acetonitrile at ambient temperature to yield anellated 9,10-dihydrophenanthrene products 3a-r in moderate to excellent yields. The [2 + 2 + 2] cocyclotrimerization products from oxa- and azabicyclic alkenes can be applied for the synthesis of polyaromatics, substituted benzo[b]triphenylenes (8a-f), via a simple Lewis acid mediated deoxyaromatization in good yields. In addition the [2 + 2 + 2] products undergo retro Diels-Alder reaction readily, providing a new method for the synthesis of substituted phenanthrenes and for generating isobenzofurans. A plausible mechanism is proposed to account for the catalytic [2 + 2 + 2] cycloaddition reaction.
- Jayanth, Thiruvellore Thatai,Jeganmohan, Masilamani,Cheng, Chien-Hong
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- Aluminium-mediated aromatic C-F bond activation: Regioswitchable construction of benzene-fused triphenylene frameworks
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Selective synthesis of benzo[f]tetraphenes or benzo[g]chrysenes was achieved via aromatic C-F bond cleavage and unprecedented regioselective C-C bond formation depending upon the choice of aluminium reagents. On treatment with AlCl3, 2-(bipheny
- Suzuki, Naoto,Fujita, Takeshi,Amsharov, Konstantin Yu.,Ichikawa, Junji
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- Atmosphere-Controlled Palladium-Catalyzed Divergent Decarboxylative Cyclization of 2-Iodobiphenyls and α-Oxocarboxylic Acids
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A novel palladium-catalyzed divergent decarboxylative cyclization of 2-iodobiphenyls and α-oxocarboxylic acids utilizing the atmosphere as a controlled switch is reported. Under the protection of a nitrogen atmosphere, tribenzotropones are synthesized by a [4 + 3] decarboxylative cyclization. Employing a palladium/O2 system enables a [4 + 2] decarboxylative cyclization to assemble triphenylenes. Notably, preliminary mechanistic studies indicate that the formation of triphenylenes involves a double decarboxylation.
- Zhou, Liwei,Sun, Mingjie,Zhou, Fengru,Deng, Guobo,Yang, Yuan,Liang, Yun
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p. 7150 - 7155
(2021/09/18)
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- Two-in-One Strategy for the Pd(II)-Catalyzed Tandem C-H Arylation/Decarboxylative Annulation Involved with Cyclic Diaryliodonium Salts
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We report here a two-in-one strategy for the Pd(II)-catalyzed tandem C-H arylation/decarboxylative annulation between readily available cyclic diaryliodonium salts and benzoic acids. The carboxylic acid functionality can be used as both a directing group for the ortho-C-H arylation and the reactive group for the tandem decarboxylative annulation. By a step-economical double cross-coupling annulation procedure, the privileged triphenylene frameworks were efficiently constructed, which have potential applications in material chemistry.
- Hu, Tao,Xu, Kai,Ye, Zenghui,Zhu, Kai,Wu, Yanqi,Zhang, Fengzhi
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supporting information
p. 7233 - 7237
(2019/10/02)
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- Phenanthrene Synthesis by Palladium(II)-Catalyzed γ-C(sp2)-H Arylation, Cyclization, and Migration Tandem Reaction
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Phenanthrene is an important structural motif in chemistry and materials science, and many synthetic routes have been developed to construct its skeleton. However, synthesis of unsymmetric phenanthrenes remains a challenge. Here, an efficient one-pot tandem reaction for the preparation of phenanthrenes via sequential γ-C(sp2)-H arylation, cationic cyclization, dehydration, and 1,2-migration was developed. A wide range of symmetric and unsymmetric phenanthrenes with diversified functional groups were synthesized with good to excellent yields.
- Gou, Bo-Bo,Yang, Hui,Sun, Huai-Ri,Chen, Jie,Wu, Junliang,Zhou, Ling
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supporting information
p. 80 - 84
(2019/01/11)
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- Aromatic Metamorphosis of Dibenzofurans into Triphenylenes Starting with Nickel-Catalyzed Ring-Opening C-O Arylation
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A new class of aromatic metamorphosis has been developed in which dibenzofurans were converted into triphenylenes. This transformation is composed of three successive operations: (1) nickel-catalyzed ring-opening C-O bond arylation with arylmagnesium bromides, (2) trifluoromethanesulfonylation (triflation) of the resulting hydroxy moiety with Tf2O, and (3) palladium-catalyzed or photoinduced ring closure. In the last ring-closing step, the photoinduced process has proven to be more productive than the palladium-catalyzed one. By employing π-extended dinaphthofuran as the substrate, dorsally benzo-fused [5]helicene was obtained in a satisfactory yield.
- Kurata, Yuto,Otsuka, Shinya,Fukui, Norihito,Nogi, Keisuke,Yorimitsu, Hideki,Osuka, Atsuhiro
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supporting information
p. 1274 - 1277
(2017/03/22)
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- Palladium-Assisted "Aromatic Metamorphosis" of Dibenzothiophenes into Triphenylenes
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Abstract Two new palladium-catalyzed reactions of aromatic sulfur compounds enabled the conversion of dibenzothiophenes into triphenylenes in four steps. This transformation of one aromatic framework into another consists of 1) 4-chlorobutylation of the dibenzothiophene to form the corresponding sulfonium salt, 2) palladium-catalyzed arylative ring opening of the sulfonium salt with a sodium tetraarylborate, 3) an intramolecular SN2 reaction to form a teraryl sulfonium salt, and 4) palladium-catalyzed intramolecular C-S/C-H coupling through electrophilic palladation. Symmetrical as well as unsymmetrical triphenylenes of interest were synthesized in a tailor-made fashion in satisfactory overall yields. A change of heart: The invention of two palladium-catalyzed arylation reactions of organosulfur compounds enabled the transformation of dibenzothiophenes into triphenylenes and thus a fundamental change in the core aromatic structure (see scheme). Both symmetrical and unsymmetrical triphenylenes were synthesized in a tailor-made fashion in satisfactory overall yield.
- Vasu, Dhananjayan,Yorimitsu, Hideki,Osuka, Atsuhiro
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supporting information
p. 7162 - 7166
(2015/06/08)
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- Triflic acid promoted synthesis of polycyclic aromatic compounds
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The triflic acid (CF3SO3H) promoted cyclizations of 2-styrylbiaryls are found to be useful for the synthesis of polycyclic aromatic compounds, including functionalized derivatives of polycyclic aromatic compounds and heterocyclic sys
- Li, Ang,DeSchepper, Daniel J.,Klumpp, Douglas A.
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scheme or table
p. 1924 - 1927
(2009/09/05)
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- Functionalized Enantiomerically Pure -, -, -, and Triblattanes
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The methylene (2, 7, 10) and spirocyclopropane derivatives (8, 11, 12) are made accessible from rac-trishomocubane(mono-, di-, tri-)ones and optically pure unsaturated and benzoannulated - (19, 48), - (30, 53), and D3-symmetrical triblattanes (3, 4) from the enantiomers of these ketones by expeditious (one pot) ring enlargement and olefination procedures.In the case of the central trienes (+)-3/(-)-3, novel members of the (CH)14 family, optical resolution is advantageously postponed to the stage of the intermediate triones (35, 41) and effected via their (R,R)-2,3-butanediol acetals.In the α-diketone series only the dione (70) is sufficiently stable to allow isolation; tetrone 73 and hexone 5 are indirectly identified as quinoxalines 74 and 76; respectively.Tribenzotriblattane (-)-4 is established as the M-helical enantiomer by X-ray crystallography.Generally the thermal stabilization pathway of unsaturated and benzoannulated triblattanes is a cycloreversion with the primary cycloreversion products 2,7>tetradeca-3,5,9,11,13-pentane (78) from rac-3> being unstable under the drastic reaction conditions required.The stereochemical course of the perepoxidation of rac-3 is investigated. - Key Words: Trishomocubanes/ Spirocyclopropanes/ -, -, -, Triblattanes
- Mueller-Boetticher, Hermann,Fessner, Wolf-Dieter,Melder, Johann-Peter,Prinzbach, Horst,Gries, Stefan,Irngartinger, Hermann
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p. 2275 - 2298
(2007/10/02)
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- A Rapid, Convergent, and Regioselective Synthesis of Anthracenes
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Anthracenes are obtained in moderate to good yield by the simultaneous treatment of benzocyclobutenols and halobenzenes with LTMP in tetrahydropyran.In the key step of this one-pot process, o-toluoyl anion intermediates from the known ring-opening of benzocyclobutenoxides add to halobenzene derived arynes.Methoxy-substituted benzocyclobutenols which are readily made regiospecifically by known methods also react regiospecifically with the single benzyne generated from either a 2- or 3-haloanisole.For example, the only trimethoxyanthracene isolated (48percent yield) from the reaction of 6-methoxybenzocyclobutenol (8) with 5-chloro-1,3-dimethoxybenzene is the 1,3,8-isomer 20.When 1,2-dihydrocyclobutaphenanthren-1-ol (14) and/or halonaphthalenes are the reactants, benzannulated anthracenes are formed; e.g., tribenzanthracene in 68percent yield from 14 and bromonaphthalene.In another extension, pentaphene (31) was made in one pot from o-dichlorobenzene.
- Fitzgerald, John J.,Drysdale, Neville E.,Olofson, R. A.
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p. 7122 - 7126
(2007/10/02)
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- Benzannulated Isobenzofurans
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A number of arynes, generated by treatment of haloarenes with sodium or potassium amide in tetrahydrofuran, were trapped with furan.The resulting dihydro epoxy arenes were converted into the following annulated isobenzofuran derivatives by using reverse Diels-Alder methodology: naphthofuran, phenanthrofuran, pyrenofuran, pyrenofuran, anthrafuran, phenanthrofuran and phenathrofuran.Bimolecular rate constants for the addition of maleic anhydride to these furans were measured, and were correlated with the Herndon structure count.Addition of arynes to selected members of this furan series yielded adducts which were deoxygenated to afford polycyclic aromatic hydrocarbons.
- Moursounidis, John,Wege, Dieter
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p. 235 - 249
(2007/10/02)
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- Isobenzofuran-Aryne Cycloadducts: Formation and Regioselective Conversion to Anthrones and Substituted Polycyclic Aromatics
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Several substituted anthracenes, benzanthracenes, dibenzanthracene, and more complex ring system derivatives are formed by the cycloaddition of 1,3-bis(trimethylsilyl)isobenzofuran (2) with arynes generated by LTMP-induced dehydrohalogenation of readily accessible haloaromatics.The cycloadducts undergo a novel acid-induced conversion to anthracenones.For several substrates this reaction is highly regioselective, allowing position specific introduction of another substituent at this stage.Reduction/dehydration of the anthrones provides an expeditious route to various polycyclic aromatic hydrocarbons.
- Netka, Jill,Crump, Stephen L.,Rickborn, Bruce
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p. 1189 - 1199
(2007/10/02)
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- Novel Annelation Reaction: Synthesis of Polycyclic Hydrocarbons from o-Quinones
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A novel general synthesis of polycyclic aromatic ring systems involving initial reaction of polycyclic o-quinone with lithium acetylide, reduction of the resulting diacetylenic diol with LiAlH4 to the corresponding divinyl diol, and finally cyclization and dehydration with HI or POCl3 to a polyarene having one more aromatic ring is reported.Syntheses of triphenylene, dibenzanthracene, benzopyrene, and benzochrysene by this means from phenanthrene-9,10-dione, benzanthracene-5,6-dione, pyrene-4,5-dione, and chrysene-5,6-dione, respectively, are described.Yields are high (94-97percent) in the initial two steps and good (52-74percent) in the final stage.The divinyl diol intermediates may be generated directly, though in lower yield, via direct reaction of the quinones with vinylmagnesium bromide or vinyllithium reagents.Various related reactions are also explored, and evidence concerning the stereochemistries of the intermediates and the mechanisms of these reactions is discussed.
- Sukumaran, Kutikat B.,Harvey, Ronald G.
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p. 2740 - 2745
(2007/10/02)
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