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Azuleno[5,6-c]furan and 4-chloroazuleno[4,5-c]furan have been prepared by a tandem cycloaddition-cycloreversion strategy. These azulenofurans are qualitatively more stable than isobenzofuran and were characterised spectroscopically and as their Diels-Alder adducts with N-methylmaleimide. 相似文献
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Yoshimasa Fukazawa Satoshi Harada Akira Inai Toshiya Okajima 《Tetrahedron letters》1993,34(52):8493-8496
The title compound (2) has been synthesized, the structure and the physical properties of which are investigated by X-ray, spectroscopic analyses, and MO calculations. There exists charge transfer (CT) interaction between the tropylium ion and the facing phenyl ring. From the pKR+ value of 2, it can be clear that the cation 2 is stabilized by the CT interaction. In spite of the presence of bond weakening σ-π orbital mixing, the cation 2 withstands retro[4+4]type bond cleavage, which is quite interesting when compared to a facile cleavage for the congener with anthracene photodimer type structure. 相似文献
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《Tetrahedron letters》2014,55(51):7089-7093
We performed X-ray structural analyses of the five- and six-layered [3.3]metacyclophanes (MCPs) 1 and 2 and the six-layered [3.3]MCP tetraone 3. In the solid state, the MCP moieties of 1, 2, and 3 adopt different conformations from those of the free MCPs in solution. In the five-layered [3.3]MCP 1, all the [3.3]MCP moieties adopt anti (chair/boat) conformations. In the six-layered [3.3]MCP 2, two three-layered [3.3]MCPs are connected by a [3.3]MCP in the anti conformation with completely parallel benzene rings. In the six-layered [3.3]MCP tetraone 3, the outer [3.3]MCP moieties and diones adopt general syn and anti geometries, respectively. However, the inner [3.3]MCP moiety adopts an anti geometry. Based on density functional theory (DFT) calculations, the most stable conformers of 1, 2, and 3 are syn (chair/chair) in the [3.3]MCP moieties and anti (twist boat/twist boat) in the dione moieties. 相似文献
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The title compound a novel cyclophane containing p-tropoquinone, was synthesized starting from 5-methoxytropolone and its physical properties were discussed comparing with those of 3,7-dimethyl-p-tropoquinone and p-benzoquinonophane. The reduced quinone character exhibited by was ascribed to the intramolecular CT interaction and the deformation of the quinone ring. 相似文献
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Two cyclophanes, [2.2](2,6)biphenylenophane and [2](2,6)biphenyleno[2](2,6)naphthalenophane, were prepared. 相似文献
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Four azuleno(2,6)pyridinophanes (1–4) were synthesized and their conformations were found by NMR spectroscopy to be very similar to those of the corresponding azulenometacyclophanes. A transverse conformational change was observed for [2.2](5,7)azuleno(2,6)pyridinophane. 相似文献
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Masahiko Shibahara Motonori Watanabe Chang Yuan Teruo Shinmyozu 《Tetrahedron letters》2011,52(39):5012-5015
In the solid state, the cyclophane (CP) moieties of the charge-transfer (CT) complexes of four- and five-layered [3.3]metacyclophanes (MCPs) 1 and 2 with tetracyanoethylene (TCNE) take different conformations from those in the solid state of the free MCPs. In the four-layered [3.3]MCP 1-TCNE complex, the CP moiety takes an s-shaped syn-anti-syn geometry, whereas the inner three benzene rings take the all-syn geometry and the two outer [3.3]MCP moieties have deformed anti-conformations in the five-layered [3.3]MCP 2-TCNE complex. In the crystal-packing diagrams of each complex, intermolecular CH/π-type interactions are observed between adjacent molecules. 相似文献
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Hisatoshi Konishi Kazunari Tanaka Yuki Teshima Takayuki Mita Osamu Morikawa Kazuhiro Kobayashi 《Tetrahedron letters》2006,47(24):4041-4044
The nucleophilic aromatic substitution of 1,5-difluoro-2,4-dinitrobenzene with 2-propylresorcinol in Et3N/CH3CN produces a mixture of syn and anti conformers of the cyclic tetramer and the cyclic hexamer with a kinetically controlled product distribution. Moreover, the reaction in DMF was catalyzed by CsF to also produce a mixture of these cyclic oligomers. In this case, however, the C-O bond is cleaved by the fluoride ion and the cyclization reaction is reversible; therefore, in the presence of excess CsF, the thermodynamically favored product (syn-isomer of cyclic tetramer) is obtained as the major product. The structures of the two conformational isomers of cyclic tetramers were determined by X-ray crystallography. 相似文献
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New pyridylmethyl armed-monoazadithiaoxa- and monoazatrithia-12-crown-4 have been prepared. The structures of the Ag+ complexes of the new ligands were investigated by X-ray crystallography, 1H NMR titrations, and FAB-MS measurements. In all cases, the Ag+ complexes form dimetallo[3.3]para- or metacyclophane structures depending on the position of the N atom of the pyridine rings. 相似文献
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Atropisomeric (R,R)-2,2'-bi([2]paracyclo[2](5,8)quinolinophane) [(R,R)-1] and (R,R)-1,1'-bi([2]paracyclo[2](5,8)isoquinolinophane) [(R,R)-2] have been prepared in moderate overall yield (17 and 9%, respectively) by a four-step sequence starting from (R)-(-)-4-amino[2.2]paracyclophane and (R)-(-)-4-carboxy[2.2]paracyclophane, respectively. The structures have been determined on the basis of NOE (1)H NMR analysis and molecular mechanics (MM) calculations performed with a Spartan02 program, using the MMF94s force field. A preliminary, qualitative analysis of the chiroptical properties of these two compounds has also been attempted. The main spectral data can be interpreted in terms of an almost planar 2,2'-bisquinoline chromophore inserted in a paracyclophane structure in the case of (R,R)-1, while in the case of (R,R)-2, the main role is played by a distorted 1,1'-bisisoquinoline chromophore. On the basis of the above structural results, a hypothesis about the enantioselection capability of these two molecules has also been formulated. 相似文献
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《Tetrahedron letters》1988,29(46):5961-5964
The title compound, the first stacked [2.2]orthotroponophane, was synthesized to elucidate the transannular interaction between upper and lower decks. 相似文献
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A new preparative sequence from 2,3-polymethylene-2-cyclopentenone 5 to 2,6-polymethylenebromobenzenes 3 (n = 6, 7, 10) and 2,6-polymethylenephenyllithiums 6 has been found. The reaction of 6 with various electrophiles produces a number of new compounds to disclose the unique reactivity of the aryl C-Li moiety surrounded by the polymethylene chain. Photolysis of 3a and 3b provides transannular products 8, 10 and 11, all arising from the proximity between the aromatic bromine and the aliphatic hydrogen intraannularly opposed to be removed as HBr. Spectrometric study gives quantitative data of the dependence of the molecular geometry upon the chain length and the aromatic substituents. The energy barriers ΔGc≠ of the conformational flipping are 17·4 kcal/mol (Tc 76·5°) for [6]metacyclophane (7a), 11·5 kcal/mol (Tc ?28°) for [7]metacyclophane (7b), ·8 kcal/mol for [10]metacyclophane (7c). The lower-energy process of the aliphatic chain in [6]metacyclophane derivatives is the pseudorotation with substituent-dependent barrier ΔGc≠ 11·1 kcal/mol (Tc ?31·5°) for 7a, 12·4 kcal/mol (Tc ?4·5°) for 3a and 12·7 kcal/mol (Tc 1·0°) for 12a. The rather large rotational barrier is attributed to the compressed structure of each system. The benzene ring distortion of the cyclophanes is deduced from the bathochromic shift of the B-band and the diamagnetic shift of the benzene proton signals in the PMR. 相似文献
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The title compounds2, 3, and4 have been prepared for configurational and conformational studies—mainly in comparison with cyclophanes of related structures, such as [2.2]orthocyclophane (1).Whereas the benchrotreno derivative2 was accessible in one step from1 and Cr(CO)6, the ferrocenophanes3 and4 were prepared by a stepwise reaction sequence starting with a Wittig reaction: thereby hydroxymethylated ferrocenyl phenyl and diferrocenyl ethylenes were obtained in which (after hydrogenation to the corresponding ethanes) the CH2OH groups were transformed into acetic acid residues. Subsequent ringclosure and reduction of the cyclic ketones19 and33 afforded the desired phanes, of which the diferroceno derivative4 was obtained as a 31 mixture of thetrans andcis isomersa andb, resp. The configurational assignment was based mainly on the1H-nmr spectra.Conformational possibilities especially of4 are briefly discussed and tentative conformations are assigned to the stereoisomers of4.
Partly reported at the VIII. International Congress on Organometallic Chemistry inKyoto (Japan), 12–16 Sept. 1977. 相似文献
Synthesen und Stereochemie von Metallocenocycloocta-1,5-dienen: [2]Orthocyclo[2](1,2)benchrotrenophan und-ferocenophan, [2.2](1,2)Ferrocenophan
Zusammenfassung Die im Titel genannten Verbindungen2, 3 und4 wurden im Hinblick auf die Untersuchung ihrer Konfiguration und Konformation — vor allem im Vergleich mit Cyclophanen verwandter Struktur, wie [2.2]Orthocyclophan (1) — dargestellt.Während das Benchrotrenderivat2 in einem Schritt aus1 und Cr(CO)6 zugänglich war, wurden die Ferrocenophane3 und4 ausgehend von einer Wittigreaktion schrittweise aufgebaut: Dabei erhielt man hydroxymethylierte Ferrocenyl-phenyl- und Diferrocenyl-ethylene, in denen — nach Hydrierung zu den entsprechenden Ethanen — die CH2OH-Gruppen in Essigsäurereste umgewandelt wurden. Anschließender Ringschluß und Reduktion der cyclischen Ketone19 und33 lieferten die gewünschten Phane, von denen das Diferrocenoderivat4 als 3:1-Mischung dertrans- undcis-Isomerena bzw.b erhalten wurde. Die konfigurative Zuordnung erfolgte vor allem auf Grund der1H-NMR-Spektren.Die konformativen Möglichkeiten — vor allem von4 — werden kurz diskutiert und vorläufige Konformationen für die Stereoisomeren von4 vorgeschlagen.
Partly reported at the VIII. International Congress on Organometallic Chemistry inKyoto (Japan), 12–16 Sept. 1977. 相似文献
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The Diels-Alder reaction of 1,2-dimethylene[2.n]MCPs (MCP = metacyclophane) with suitable dienophiles followed by aromatization and photoinduced or FeCl(3)-induced transannular cyclization afforded phenanthrene-anellated polycyclic aromatic hydrocarbons, which were found to adopt helical chirality in the solid state. 相似文献