5406-90-6Relevant academic research and scientific papers
Open-shell and antiaromatic character induced by the highly symmetric geometry of the planar heptalene structure: Synthesis and characterization of a nonalternant isomer of bisanthene
Konishi, Akihito,Horii, Koki,Shiomi, Daisuke,Sato, Kazunobu,Takui, Takeji,Yasuda, Makoto
supporting information, p. 10165 - 10170 (2019/08/20)
A nonbenzenoid hydrocarbon, difluoreno-[1,9,8-alkj:1′,9′,8′-gfed]heptalene 1, is synthesized. Experimental and theoretical investigations demonstrate that the planar and symmetric heptalene core within 1 effectively induces the antiaromatic and open-shell character. These properties are not shared by bisanthene 2, a benzenoid isomer of 1.
Open-Shell and Antiaromatic Character Induced by the Highly Symmetric Geometry of the Planar Heptalene Structure: Synthesis and Characterization of a Nonalternant Isomer of Bisanthene
Konishi, Akihito,Horii, Koki,Shiomi, Daisuke,Sato, Kazunobu,Takui, Takeji,Yasuda, Makoto
supporting information, p. 10165 - 10170 (2019/08/28)
A nonbenzenoid hydrocarbon, difluoreno[1,9,8-alkj:1′,9′,8′-gfed]heptalene 1, is synthesized. Experimental and theoretical investigations demonstrate that the planar and symmetric heptalene core within 1 effectively induces the antiaromatic and open-shell character. These properties are not shared by bisanthene 2, a benzenoid isomer of 1.
Chemical Consequences of the Intramolecular Interaction between a Sulphur Atom and a Methoxycarbonyl Group in Fluorene Systems
Nakanishi, Waro,Kusuyama, Yoshiaki,Ikeda, Yoshitsugu,Oki, Michinori
, p. 799 - 804 (2007/10/02)
The intramolecular interaction between a sulphur atom and a methoxycarbonyl group was found to affect their chemical reactivity.The rates of C-S bond cleavage in methyl-9,9-bis(ethylthio)fluorene-x-carboxylate, where x is 1, 2, or 3, with sodium ethanethiolate show that the rate is minimal, though comparable with the others, when x=1, because of steric effects.In contrast, methyl 9-(ethylthio)fluorene-x-carboxylates, where x=1, 2, or 3, exhibit the maximum rate when x=1.The rates of ester exchange in the presence of toluene-p-sulphonic acid indicate that the reaction is accelerated by the presence of two ethylthio groups at the 9 position of methyl fluorene-1-carboxylate but no significant effect is detected if there is only one ethylthio group.The hydrolysis of the thioketal group in 9,9-bis(ethylthio)fluorene is also accelerated by the presence of a 1-methoxycarbonyl group.The implication of these results are discussed with the use of a model compound.
Synthesis and Structure of a New Stable Carbocation Stabilized by Two Neighboring Sulfur Atoms. Dimethyl-9,9-bis(methylthio)-1-fluorenylcarbenium Ion
Hojo, Masaru,Ichi, Tadaaki,Shibato, Kishio
, p. 1478 - 1482 (2007/10/02)
9,9-Bis(methylthio)-1-isopropenylfluorene (3) and the corresponding alcohol 2 generate a carbocation 1 in trifluoroacetic acid solution at room temperature.This ion is sufficiently stable to be observed spectroscopically in this solution.A stable crystalline hexachloroantimonate of 1 was isolated.In trifluoroacetic acid-d at room temperature, the two C+-methyl groups of 1 undergo H-D isotopic exchange to give the corresponding hexadeuterio cation.On the basis of electronic and 1H NMR spectroscopic data at temperatures from 40 to -60 deg C, it is concluded that ion 1 is not a sulfonium species but exists as a carbocation stabilized by electrons from the two neighboring sulfur atoms.Carbon-13 NMR data show that the positive charge is extensively delocalized over the neighboring sulfur atoms, with small amount remaining on the carbon atom.The possibility is suggested that 1 is a pentacoordinated carbon species that resembles the transition states in SN2 displacements.
