- The structure of hexabenzotriphenylene and the problem of overcrowded "D3h" polycyclic aromatic compounds
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Hexabenzotriphenylene (1, dibenzo[f,j]phenanthro[9,10-s]picene) has been prepared in 5% yield by vacuum pyrolysis of phenanthrene-9,10-dicarboxylic anhydride, and its X-ray structure has been determined. Compound 1 is a strongly twisted, D3-symmetric molecular propeller, in contrast to other highly substituted triphenylenes (perfluoro- and perchlorotriphenylene) which adopt C2-symmetric conformations. Computational studies of these and other overcrowded, nominally D3h,-symmetric, polycyclic aromatic compounds are reported, and the origins of their conformational preferences and the adequacy of various computational methods for treating these compounds are discussed.
- Barnett, Lisa,Ho, Douglas M.,Baldridge, Kim K.,Pascal Jr., Robert A.
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- Kinetic Control in the Palladium-Catalyzed Synthesis of C2-Symmetric Hexabenzotriphenylene. A Conformational Study
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(Equation Presented) The hitherto unisolated, thermodynamically unstable C2-symmetric conformer of hexabenzotriphenylene (1) has been efficiently synthesized by palladium-catalyzed cyclotrimerization of 9,10-didehydrophenanthrene (4). The barriers to conformational interconversion of 1 are examined experimentally and by computational studies.
- Pen?a, Diego,Cobas, Agusti?n,Pe?rez, Dolores,Guitia?n, Enrique,Castedo, Luis
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- Synthesis of hexabenzotriphenylene and other strained polycyclic aromatic hydrocarbons by palladium-catalyzed cyclotrimerization of arynes
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(matrix presented). To evaluate the potential of the recently developed palladium-catalyzed trimerization of arynes for the synthesis of strained polycyclic hydrocarbons, the trimerizations of 1,2-didehydronaphthalene (1) and 9,10-didehydrophenanthrene (2), generated from the corresponding o-trimethylsilylaryl triflates 5 and 11, respectively, were studied. The synthesis of tribenzo[a,g,o]triphenylene (6), tribenzo[a,g,m]triphenylene (7), and hexabenzo[a,c,g,i,m,o]triphenylene (12) is described.
- Pena, Diego,Perez, Dolores,Guitian, Enrique,Castedo, Luis
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- Generation of nickel(0)-aryne and nickel(II)-biphenyldiyl complexes via in situ dehydrohalogenation of arenes. Molecular structures of
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Reactions of the aromatic halides chlorobenzene, 9-bromophenanthrene and chloro-p-xylene with lithium 2,2,6,6-tetramethylpiperidide (LiTMP) in the presence of [Ni(η2-C2H4)(dcpe)] (1) generated the corresponding η2/su
- Bennett, Martin A.,Kopp, Mike R.,Wenger, Eric,Willis, Anthony C.
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- Benzocyclobutenes. Part 7. Synthesis and X-ray Crystal Structure of Cyclobutaphenanthrene-1,2-dione and the Synthesis of Hexabenzotriphenylene
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Photocycloaddition of tetrachloroethene to phenanthrene gives 1,1,2,2-tetrachloro-1,2,2a,10b-tetrahydrocyclobutaphenanthrene.Treatment of this compound with N-bromosuccinimide gives the corresponding tetrachlorodihydrocyclobutaphenanthrene which can be hydrolysed to cyclobutaphenanthrene-1,2-dione.The 1H and 13C n.m.r. spectra and X-ray molecular structure of the dione have been determined.Flash-vacuum pyrolysis of the dione gives a low yield of hexabenzotriphenylene.
- Hacker, Nigel P.,McOmie, John F. W.,Meunier-Piret, Jacqueline,Meerssche, Maurice Van
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