| Autor: |
Lin, Yun-Shan, Lin, Shih-Jue, Jiang, Shuan-Ya, Huang, Tian-Chyuan, Huang, Chien-Yu, Kurihara, Teruo, Mori, Akira, Morita, Tadayoshi, Takeshita, Hitoshi, Nozoe, Tetsuo |
| Zdroj: |
Bulletin of the Chemical Society of Japan; December 2000, Vol. 73 Issue: 12 p2793-2803, 11p |
| Abstrakt: |
The lead(IV) oxide oxidation of various azulen-2-ol derivatives in acetic acid generates azulenoxy radicals via one-electron oxidation. The intermediates end up yielding recombined dimers, [1,1′-biazulene]-2,2′(1H,1′H)-dimers, as common type of products. In addition to these, hexacyclic cage dimers were obtained from 5-substituted azulen-2-ol derivatives. From dimethyl 2-hydroxyazulene-1,3-dicarboxylate, a hydroxyazulene having no substituent on the seven-membered ring was isolated a pair of dimethyl 2-hydroxy-4-[1,3-di(methoxycarbonyl)-2-oxo-1,2-dihydroazulenyl]azulene-1,3-dicarboxylate, but neither a cage dimer nor a 1,6-coupled dimer. The full structures of the dimers have been firmly established by an extensive X-ray crystallographic analysis and 13C NMR spectral comparisons of the key derivatives. Concerning the mechanism of the formation of the cage dimers, a [5+5] π cycloaddition followed by recombination of the resultant biallyl system is suggested. |
| Databáze: |
Supplemental Index |
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