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Michael J Krische - One of the best experts on this subject based on the ideXlab platform.
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alternating oligo o p phenylenes via ruthenium catalyzed diol diene Benzannulation orthogonality to cross coupling enables de novo nanographene and pah construction
Chemical Science, 2018Co-Authors: Zachary A Kasun, Hiroki Sato, Jon A. Bender, Sean T. Roberts, Jing Nie, Yasuyuki Mori, Michael J KrischeAbstract:Ruthenium(0) catalyzed diol–diene Benzannulation is applied to the conversion of oligo(p-phenylene vinylenes) 2a–c, 5 and 6 to alternating oligo(o,p-phenylenes) 10a–c, 11–13. Orthogonality with respect to conventional palladium catalyzed biaryl cross-coupling permits construction of p-bromo-terminated alternating oligo(o,p-phenylenes) 10b, 11–13, which can be engaged in Suzuki cross-coupling and Scholl oxidation. In this way, structurally homogeneous nanographenes 16a–f are prepared. Nanographene 16a, which incorporates 14 fused benzene rings, was characterized by single crystal X-ray diffraction. In a similar fashion, p-bromo-terminated oligo(p-phenylene ethane diol) 9, which contains a 1,3,5-trisubstituted benzene core, is converted to the soluble, structurally homogeneous hexa-peri-hexabenzocoronene 18. A benzothiophene-terminated pentamer 10c was prepared and subjected to Scholl oxidation to furnish the helical bis(benzothiophene)-fused picene derivative 14. The steady-state absorption and emission properties of nanographenes 14, 16a,b,d,e,h and 18 were characterized. These studies illustrate how orthogonality of ruthenium(0) catalyzed diol–diene Benzannulation with respect to classical biaryl cross-coupling streamlines oligophenylene and nanographene construction.
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Helical Rod-like Phenylene Cages via Ruthenium Catalyzed Diol-Diene Benzannulation: A Cord of Three Strands
2018Co-Authors: Hiroki Sato, Jon A. Bender, Sean T. Roberts, Michael J KrischeAbstract:p-Bromo-terminated oligo(p-phenylenevinylenes) emanating from a 1,3,5-benzene core are dihydroxylated and subjected to ruthenium catalyzed diol-diene Benzannulation to form tripodal oligo(phenylenes). Copper- or nickel-mediated 3-fold reductive biaryl homocoupling delivers a series of triple-stranded phenylene cages of helical rod-like topology bearing 14, 17, and 20 benzene rings
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Benzannulation via ruthenium catalyzed diol diene 4 2 cycloaddition one and two directional syntheses of fluoranthenes and acenes
ChemInform, 2014Co-Authors: Laina M Geary, Teyu Chen, Patrick T Montgomery, Michael J KrischeAbstract:A new Benzannulation protocol is developed consisting of Ru-catalyzed diol-diene [4 + 2] cycloaddition and subsequent aromatization upon dehydration or deoxydehydration is developed to allow the synthesis of a diverse range of polycyclic arenes.
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Benzannulation via ruthenium catalyzed diol diene 4 2 cycloaddition one and two directional syntheses of fluoranthenes and acenes
Journal of the American Chemical Society, 2014Co-Authors: Laina M Geary, Teyu Chen, Patrick T Montgomery, Michael J KrischeAbstract:A new Benzannulation protocol is described and applied to the synthesis of polycyclic aromatic hydrocarbons. Ruthenium(0)-catalyzed diol–diene [4+2] cycloaddition delivers cyclohex-1-ene-4,5-diols, which are subject to aromatization upon dehydration or Nicholas diol deoxydehydration. Employing diol and tetraol reactants, Benzannulation can be conducted efficiently in one- and two-directional modes, respectively, as illustrated in the construction of substituted fluoranthenes and acenes.
You Huang - One of the best experts on this subject based on the ideXlab platform.
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one pot synthesis of polysubstituted benzenes through a n n dimethyl 4 aminopyridine dmap catalyzed 4 2 Benzannulation of 1 3 bis sulfonyl butadienes and γ substituted allenoates
Chemistry-an Asian Journal, 2016Co-Authors: Meijia Chang, Jie Zheng, You HuangAbstract:A new strategy for the one-pot synthesis of polysubstituted benzenes through a N,N-dimethyl-4-aminopyridine (DMAP)-catalyzed [4+2] Benzannulation from readily prepared 1,3-bis(sulfonyl)butadienes and γ-substituted allenoates is described. This method provides a facile, metal-free and general route to highly substituted benzenes under mild conditions in moderate-to-good yields with complete regioselectivity.
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phosphine catalyzed domino Benzannulation an efficient method to construct biaryl skeletons
Organic Letters, 2013Co-Authors: Jie Zheng, You HuangAbstract:The first phosphine-catalyzed domino Benzannulation reaction to prepare a variety of functionalized biaryls from allenoates and dienic sulfones is developed.
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phosphine mediated domino Benzannulation strategy for the construction of highly functionalized multiaryl skeletons
ChemInform, 2012Co-Authors: Peizhong Xie, You Huang, Ruyu ChenAbstract:A diversity of polyphenyl dicarboxylates is prepared by phosphine-mediated domino Benzannulation reaction of allylic carbonates, e.g. (I), with β,γ-unsaturated α-ketoesters, e.g. (II).
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phosphine mediated domino Benzannulation strategy for the construction of highly functionalized multiaryl skeletons
Chemistry: A European Journal, 2012Co-Authors: Peizhong Xie, You Huang, Ruyu ChenAbstract:A skeleton crew: A phosphine-mediated domino Benzannulation strategy was developed for the synthesis of multiaryl skeletons (see scheme). A wide range of aromatic compounds and functional groups can be assembled into a multiaryl molecule through a core domino process.
Yoshinori Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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rhodium catalyzed oxidative Benzannulation of n adamantyl 1 naphthylamines with internal alkynes via dual c h bond activation synthesis of substituted anthracenes
Organic Letters, 2016Co-Authors: Xuan Zhang, Yoshinori Yamamoto, Abdulrahman I Almansour, Natarajan Arumugam, Raju Suresh Kumar, Ming BaoAbstract:Rhodium-catalyzed oxidative Benzannulation of N-adamantyl-1-naphthylamines with internal alkynes to produce highly substituted anthracenes in satisfactory to good yields was developed. The annulation reaction proceeded smoothly under mild conditions in the presence of [Cp*RhCl2]2 as the precatalyst and Cu(OAc)2 as the oxidant.
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efficient method for synthesis of angucyclinone antibiotics via gold catalyzed intramolecular 4 2 Benzannulation enantioselective total synthesis of ochromycinone and rubiginone b2
Journal of Organic Chemistry, 2005Co-Authors: Kenichiro Sato, Naoki Asao, Yoshinori YamamotoAbstract:An efficient synthetic approach to angucyclinone antibiotics, (+)-ochromycinone and (+)-rubiginone B2, is reported. The key step involves the facile formation of 2,3-dihydrophenantren-4(1H)-one skeleton, an important framework of angucyclinone natural products, by using gold-catalyzed intramolecular [4 + 2] Benzannulation reaction.
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lewis acid catalyzed Benzannulation via unprecedented 4 2 cycloaddition of o alkynyl oxo benzenes and enynals with alkynes
Journal of the American Chemical Society, 2003Co-Authors: Naoki Asao, Tsutomu Nogami, And Sunyoung Lee, Yoshinori YamamotoAbstract:The reaction of o-alkynyl(oxo)benzenes 1 with alkynes 2 in the presence of a catalytic amount of AuCl3 in (CH2Cl)2 at 80 °C gave the [4+2] Benzannulation products, naphthyl ketone derivatives 3 and 4, in high yields. When the reaction was carried out using AuBr3 instead of AuCl3, the reaction speed was enhanced and the chemical yield was increased. On the other hand, when the reaction was carried out in the presence of a catalytic amount of Cu(OTf)2 and 1 equiv of a Bronsted acid, such as CF2HCO2H, in (CH2Cl)2 at 100 °C, the decarbonylated naphthalene products 5 were obtained in high yields. Similarly, the Cu(OTf)2−H2O-promoted reaction of the enynals 7 with an alkyne 2 afforded the corresponding [4+2] Benzannulation products, decarbonylated benzene derivatives 8, in good yields. Both AuX3- and Cu(OTf)2-catalyzed Benzannulations proceed most probably through the formation of the benzo[c]pyrylium ate complex 10, the Diels−Alder addition of alkynes 2 to the ate complex, and the resulting bicyclic pyrylium i...
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synthesis of 6h dibenzo b d pyran 6 ones from aryl 3 bromopropenoates via a sequential one pot procedure using the sonogashira coupling Benzannulation reaction
Journal of Organic Chemistry, 2002Co-Authors: Taishi Kawasaki, Yoshinori YamamotoAbstract:Various kinds of 6H-dibenzo[b,d]pyran-6-ones 4 were synthesized via a sequential one-pot procedure using the Sonogashira coupling-Benzannulation reaction of aryl 3-bromopropenoates 1, in which the ortho-position of aryl group is substituted with enynes or iodine, with acetylenes 2 in the presence of palladium and copper catalysts. The Sonogashira coupling between the aryl 3-bromopropenoates 1a and 1b, bearing enynes at the ortho-position of aryl group, and alkynes 2a-g gave the enyne intermediates 3 in situ, which subsequently underwent the palladium-catalyzed Benzannulation reaction to afford the 6H-dibenzo[b,d]pyran-6-ones 5a-g and 6. The Sonogashira coupling between the aryl 3-bromopropenoate 1c, bearing iodine at the ortho-position of aryl group, and diynes 2f and 2h produced the diyne intermediates 13, which underwent the Benzannulation reaction to afford the 6H-dibenzo[b,d]pyran-6-ones 14f and 14h.
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Synthesis of phthalides and 3,4-dihydroisocoumarins using the palladium-catalyzed intramolecular Benzannulation strategy.
The Journal of organic chemistry, 2002Co-Authors: Taishi Kawasaki, Shinichi Saito, Yoshinori YamamotoAbstract:A novel method for the synthesis of phthalides and 3,4-dihydroisocoumarins via the palladium-catalyzed intramolecular Benzannulation of bis-enyne and enyne-diyne systems is described. Various kinds of substituted phthalides 9 and 17 and 3,4-dihydroisocoumarins 19 were synthesized from 8, 16, and 18, respectively, in moderate to excellent yields. The Benzannulation reaction proceeded chemoselectively to give the corresponding fused ring compounds A without the formation of the regioisomeric products B (eq 6). Furthermore, this methodology was applied to the synthesis of biologically active 3-n-butylphthalide 23.
Yuchieh Cheng - One of the best experts on this subject based on the ideXlab platform.
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synthesis of substituted tetralins and benzosuberans via bf3 oet2 mediated formal 4 2 and 5 2 stereocontrolled cycloaddition of 4 alkenols with veratrol
Organic Letters, 2016Co-Authors: Meng-yang Chang, Yuchieh ChengAbstract:BF3·OEt2-mediated one-pot formal (4 + 2) and (5 + 2) stereocontrolled cycloaddition of 4-alkenols 3 and 4 with veratrol affords the respective substituted tetralins 5 and benzosuberans 6 in good yields. The cascade protocol combines a facile double Friedel–Crafts Benzannulation of 4-alkenols 3 and 4 (having two electrophilic sites) and veratrol (7a) (having two nucleophilic sites). A plausible mechanism was studied and proposed.
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Synthesis of Substituted Tetralins and Benzosuberans via BF3·OEt2‑Mediated Formal (4 + 2) and (5 + 2) Stereocontrolled Cycloaddition of 4‑Alkenols with Veratrol
2016Co-Authors: Meng-yang Chang, Yuchieh ChengAbstract:BF3·OEt2-mediated one-pot formal (4 + 2) and (5 + 2) stereocontrolled cycloaddition of 4-alkenols 3 and 4 with veratrol affords the respective substituted tetralins 5 and benzosuberans 6 in good yields. The cascade protocol combines a facile double Friedel–Crafts Benzannulation of 4-alkenols 3 and 4 (having two electrophilic sites) and veratrol (7a) (having two nucleophilic sites). A plausible mechanism was studied and proposed
Lei Zhou - One of the best experts on this subject based on the ideXlab platform.
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phenanthrene synthesis by eosin y catalyzed visible light induced 4 2 Benzannulation of biaryldiazonium salts with alkynes
ChemInform, 2013Co-Authors: Tiebo Xiao, Xichang Dong, Yanchi Tang, Lei ZhouAbstract:The metal-free, visible light-induced Benzannulation of biaryldiazonium salts with alkynes affords a variety of 9-substituted or 9,10-disubstituted phenanthrenes via a cascade radical addition and cyclization sequence in the presence of eosin Y as a photoredox catalyst.
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phenanthrene synthesis by eosin y catalyzed visible light induced 4 2 Benzannulation of biaryldiazonium salts with alkynes
Advanced Synthesis & Catalysis, 2012Co-Authors: Tiebo Xiao, Xichang Dong, Yanchi Tang, Lei ZhouAbstract:A metal-free, visible light-induced [4+2] Benzannulation of biaryldiazonium salts with alkynes was developed. With eosin Y as photoredox catalyst, a variety of 9-substituted or 9,10-disubstituted phenanthrenes were obtained via a cascade radical addition and cyclization sequence.