- 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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- A novel and efficient synthesis of phenanthrene derivatives via palladium/norbornadiene-catalyzed domino one-pot reaction
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Herein we report a novel palladium-catalyzed reaction that results in phenanthrene derivatives using aryl iodides, ortho-bromoben-zoyl chlorides and norbornadiene in one pot. This dramatic transformation undergoes ortho-C–H activation, decarbonylation and subsequent a retro-Diels–Alder process. Pleasantly, this protocol has a wider substrate range, shorter reaction times and higher yields of products than previously reported methods.
- Zhong, Yue,Wu, Wen-Yu,Yu, Shao-Peng,Fan, Tian-Yuan,Yu, Hai-Tao,Li, Nian-Guang,Shi, Zhi-Hao,Tang, Yu-Ping,Duan, Jin-Ao
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supporting information
p. 291 - 298
(2019/02/20)
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- Facile synthesis of 1,2-dione-containing abietane analogues for the generation of human carboxylesterase inhibitors
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Recently, a series of selective human carboxylesterase inhibitors have been identified based upon the tanshinones, with biologically active molecules containing a 1,2-dione group as part of a naphthoquinone core. Unfortunately, the synthesis of such compounds is complex. Here we describe a novel method for the generation of 1,2-dione containing diterpenoids using a unified approach, by which boronic acids are joined to vinyl bromo-cyclohexene derivatives via Suzuki coupling, followed by electrocyclization and oxidation to the o-phenanthroquinones. This has allowed the construction of a panel of miltirone analogues containing an array of substituents (methyl, isopropyl, fluorine, methoxy) which have been used to develop preliminary SAR with the two human carboxylesterase isoforms. As a consequence, we have synthesized highly potent inhibitors of these enzymes (Ki 15 nM), that maintain the core tanshinone scaffold. Hence, we have developed a facile and reproducible method for the synthesis of abietane analogues that have resulted in a panel of miltirone derivatives that will be useful tool compounds to assess carboxylesterase biology.
- Binder, Randall J.,Hatfield, M. Jason,Chi, Liying,Potter, Philip M.
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- Regioselective Synthesis of Polycyclic and Heptagon-embedded Aromatic Compounds through a Versatile π-Extension of Aryl Halides
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A versatile π-extension reaction was developed based on the three-component cross-coupling of aryl halides, 2-haloarylcarboxylic acids, and norbornadiene. The transformation is driven by the direction and subsequent decarboxylation of the carboxyl group, while norbornadiene serves as an ortho-C?H activator and ethylene synthon via a retro-Diels–Alder reaction. Comprehensive DFT calculations were performed to account for the catalytic intermediates.
- Fu, Wai Chung,Wang, Zheng,Chan, Wesley Ting Kwok,Lin, Zhenyang,Kwong, Fuk Yee
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supporting information
p. 7166 - 7170
(2017/06/13)
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- A combined experimental and computational study on the cycloisomerization of 2-ethynylbiaryls catalyzed by dicationic arene ruthenium complexes
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Ruthenium-catalyzed cycloisomerization of 2-ethynylbiaryls was investigated to identify an optimal ruthenium catalyst system. A combination of [η6-(p-cymene)RuCl2(PR3)] and two equivalents of AgPF6 effectively converted 2-ethynylbiphenyls into phenanthrenes in chlorobenzene at 120 °C over 20 h. Moreover, 2-ethynylheterobiaryls were found to be favorable substrates for this ruthenium catalysis, thus achieving the cycloisomerization of previously unused heterocyclic substrates. Moreover, several control experiments and DFT calculations of model complexes were performed to propose a plausible reaction mechanism.
- Yamamoto, Yoshihiko,Matsui, Kazuma,Shibuya, Masatoshi
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supporting information
p. 7245 - 7255
(2015/05/05)
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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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- Regiospecific oxidation of polycyclic aromatic phenols to quinones by hypervalent iodine reagents
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The hypervalent iodine reagents o-iodoxybenzoic acid (IBX) and bis(trifluoro-acetoxy)iodobenzene (BTI) are shown to be general reagents for regio-controlled oxidation of polycyclic aromatic phenols (PAPs) to specific isomers (ortho, para, or remote) of polycyclic aromatic quinones (PAQs). The oxidations of a series of PAPs with IBX take place under mild conditions to furnish the corresponding ortho-PAQs. In contrast, oxidations of the same series of PAPs with BTI exhibit variable regiospecificity, affording para-PAQs where structurally feasible and ortho-PAQs or remote PAQ isomers in other cases. The structures of the specific PAQ isomers formed are predictable on the basis of the inherent regioselectivities of the hypervalent iodine reagents in combination with the structural requirements of the phenol precursors. IBX and BTI are recommended as the preferred reagents for regio-controlled oxidation of PAPs to PAQs.
- Wu, Anhui,Duan, Yazhen,Xu, Daiwang,Penning, Trevor M.,Harvey, Ronald G.
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experimental part
p. 2111 - 2118
(2010/04/26)
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- Hg(OTf)2-catalyzed arylene cyclization
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Novel Hg(OTf)2-catalyzed arylene cyclization was achieved with highly efficient catalytic turnover (up to 200 times). The reaction takes place via protonation of allylic hydroxyl group by in situ formed TfOH of an organomercurlc intermediate to
- Namba, Kosuke,Yamamoto, Hirofumi,Sasaki, Ikuo,Mori, Kumiko,Imagawa, Hiroshi,Nishizawa, Muaio
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supporting information; experimental part
p. 1767 - 1770
(2009/04/12)
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- Ring-closing olefin metathesis of 2,2′-divinylbiphenyls: A novel and general approach to phenanthrenes
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(Chemical Equation Presented) The ring-closing olefin metathesis (RCM) of 2,2′-divinylbiphenyls, using a second-generation RCM ruthenium-based catalyst, leads to differently substituted phenanthrenes in quantitative yield under very mild reaction conditions, independent of both nature and position of the groups present on the biphenyl moiety.
- Iuliano, Anna,Piccioli, Paolo,Fabbri, Davide
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p. 3711 - 3714
(2007/10/03)
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- Synthesis of phenanthrenes and polycyclic heteroarenes by transition-metal catalyzed cycloisomerization reactions
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Readily available biphenyl derivatives containing an alkyne unit at one of their ortho-positions are converted into substituted phenanthrenes on exposure to catalytic amounts of either PtCl2, AuCl, AuCl3, GaCl3 or InCl3 in toluene. This 6-endo-dig cyclization likely proceeds through initial π-complexation of the alkyne unit followed by interception of the resulting η2-metal species by the adjacent arene ring. The reaction is inherently modular, allowing for substantial structural variations and for the incorporation of substituents at any site of the phenanthrene product. Moreover, it is readily extended to the heterocyclic series as exemplified by the preparation of benzoindoles, benzocarbazoles, naphthothiophenes, as well as bridgehead nitrogen heterocycles such as pyrrolo[1,2-a]quinolines. Depending on the chosen catalyst, biaryls bearing halo-alkyne units can either be converted into the corresponding 10-halo-phenanthrenes or into the isomeric 9-halo-phenanthrenes; in the latter case, the concomitant 1,2-halide shift is best explained by assuming a metal vinylidene species as the reactive intermediate. The scope of this novel method for the preparation of polycyclic arenes is illustrated by the total synthesis of a series of polyoxygenated phenanthrenes that are close relatives of the anticancer agent combretastatin A-4, as well as by the total synthesis of the aporphine alkaloid O-methyl-dehydroisopiline and its naturally occurring symmetrical dimer.
- Mamane, Victor,Hannen, Peter,Fuerstner, Alois
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p. 4556 - 4575
(2007/10/03)
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- Flexible synthesis of phenanthrenes by a PtCl2-catalyzed cycloisomerization reaction
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Readily available biphenyl derivatives containing an alkyne unit at one of their ortho positions are converted into substituted phenanthrenes upon exposure to catalytic amounts of either PtCl2, AuCl3, GaCl3, or InCl3 in toluene. This 6-endo-dig cyclization likely proceeds through initial π-coordination of the alkyne unit followed by interception of the resulting η2-metal complex by the adjacent arene ring. The reaction is inherently modular, allowing for substantial structural variations and for the incorporation of substituents at any site of the phenanthrene product except C-9. Moreover, the reaction is readily applied to the heterocyclic series as exemplified by the preparation of benzoindoles, naphthothiophenes as well as bridgehead nitrogen hetero- cycles.
- Fuerstner, Alois,Mamane, Victor
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p. 6264 - 6267
(2007/10/03)
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- The directed ortho metalation - Palladium catalyzed cross coupling connection. A general regiospecific route to 9-phenanthrols and phenanthrenes. Exploratory further metalation
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A new general and regiospecific synthesis of 9-phenanthrols (1 + 2 → 3 → 4, Scheme 1, Table 1) proceeding by a Directed ortho Metalation (DoM), Suzuki-Miyaura crocs coupling, and a new LDA-mediated Directed remote Metalation sequence is described. The facile Pd-catalyzed hydrogenolysis of the phenanthrols 4 into the corresponding phenanthrenes 5 via their triflates 18 translates the original DoM regioselectivity also into a general synthesis of phenanthrenes (Table 2). Further DoM (19 → 20, 21; 24 → 25), cross coupling (20c → 23), as well as oxidation - ring contraction (4b, 4f → 28a, 28b) chemistry of phenanthrene derivatives is reported.
- Fu, Jian-Min,Snieckus, Victor
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p. 905 - 919
(2007/10/03)
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- Process for the selective production of dihydroxybenzenes
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The known nuclear hydroxylation of phenol or substituted phenols or phenol ethers with organic solutions of hydrogen peroxide in the presence of a catalyst is carried out in improved manner by employing both (1) a special, practically water free solution of hydrogen peroxide in an organic solvent which forms an azeotrope with water, which azeotrope boils below the boiling point of hydrogen peroxide, and (2) selenium dioxide as a catalyst. Through this, the nuclear hydroxylation is substantially simpler than previously. Besides, for the first time, it is possible to control the ortho to para ratio or the two ortho ratios to each other.
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- A New Phenanthrene Synthesis
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Substituted (Z)-2-chlorostilbenes give good yields of phenanthrenes on treatment with activated magnesium formed by the reduction of magnesium chloride with potassium in the presence of potassium iodide in boiling tetrahydrofuran.A homolytic substitution mechanism is proposed for this reaction.
- Brown, Charles,Sikkel, Bernardus J.,Carvalho, Christopher F.,Sargent, Melvyn V.
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p. 3007 - 3010
(2007/10/02)
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