The<i>in situ</i>-Generated Nickel(0)-catalyzed Homo-coupling of Alkenyl Halides with Zinc Powder. A Specific Outcome in Stereochemistry
作者:Kentaro Takagi、Harutaka Mimura、Saburo Inokawa
DOI:10.1246/bcsj.57.3517
日期:1984.12
The catalytic activity of nickel(0) generated in situ from nickel(II) salt was examined in a dehalogenative coupling of alkenylhalides with zinc powder. The reaction of alkenyl bromides took place provided that potassium iodide was present to assist the reduction of nickel(II) with zinc powder, and also to convert the alkenyl bromides to the corresponding alkenyl iodides. A speculative view concerning
在烯基卤化物与锌粉的脱卤偶联中检测了从镍 (II) 盐原位生成的镍 (0) 的催化活性。烯基溴化物的反应发生,前提是存在碘化钾以帮助用锌粉还原镍 (II),并将烯基溴化物转化为相应的烯基碘化物。为了解释观察到的独特立体化学,提出了关于歧化步骤的推测性观点。
Oxokohlenstoffe und verwandte Verbindungen; 21. Mitteilung.<sup>1</sup>Diels-Alder Reaktion von 3-Halogeno-3-cyclobuten-1,2-dionen mit 1,1′-Bi-1-cycloalkenylen: Synthese dicycloalkano-anellierter Dihydrobenzocyclobutendione und Benzocyclobutendione
作者:Arthur H. Schmidt、Christian Künz、Marianne Malmbak、Jörg Zylla
DOI:10.1055/s-1994-25490
日期:——
Oxocarbons and Related Compounds; Part 21.1 Diels-Alder Reactions of 3-Halogeno-3-cyclobutene-1,2-diones with 1,1′-Bi-1-cycloalkenyls. Synthesis of Dicycloalkano-annulated Dihydrobenzocyclobutenediones and Benzocyclobutenediones On controlled heating to 100°C, 3-chloro-3-cyclobutene-1,2-diones (5a) reacted with 1,1′-bi-1-cyclohexenyl (6) and 1, 1′-bi-1-cyclopentenyl (13) to give the dicycloalkano-annulated dihydrobenzocyclobutenediones 7 and 16, respectively. Treatment of carbon tetrachloride solutions of 7 and 16 with bromine at reflux temperature afforded the corresponding benzocyclobutenediones 9 and 17. Surprisingly, the reaction of 5a with 1,1′-bi-1-cycloheptenyl (14) and 1,1′-bi-1-cyclooctenyl (15) gave directly the benzocyclobutenediones 20 and 21. The hitherto unknown 3-bromo-3-cyclobutene-1,2-dione (5c) was prepared by treatment of 3-hydroxy-3-cyclobutene-1,2-dione (5b) with oxalic dibromide in 76% yield. Its reaction with the dienes 6, 13, 14 has been investigated.
Studies in mass spectrometry. Part XIV. The effect of conformation on the electron impact-induced fragmentation of adducts of p-benzoquinone and 1,1′-bicycloalkenyls
作者:Joseph Deutsch、Asher Mandelbaum
DOI:10.1039/j29710000886
日期:——
Electron impact-induced doublehydrogenmigration leading to the formation of ions a from adducts of p-benzoquinone and 1,1′-bicycloalken-1-yls has been found to be suppressed when the sizes of rings C and D of the adducts are increased. This effect is explained in terms of different distances between the migrating hydrogen atoms and the carbonyl groups, which are affected by the conformations of the