Diastereofacial selectivity in reactions of substituted cyclohexyl radicals. An experimental and theoretical study
作者:W. Damm、B. Giese、J. Hartung、T. Hasskerl、K. N. Houk、O. Hueter、H. Zipse
DOI:10.1021/ja00037a007
日期:1992.5
diastereofacial selectivity in reactions of a series of alkyl-substituted cyclohexyl radicals has been investigated. In additions of cyclohexyl radicals to alkenes, it has been found that only substituents bound at the olefinic center being attacked by the radical influence the equatorial-axial selectivity. Substituents bound to the radical center or axial substituents p to the radical center lead to increased
已经研究了一系列烷基取代的环己基自由基反应中的非对映选择性。除了向烯烃添加环己基之外,已经发现只有在烯烃中心结合的取代基被自由基攻击会影响赤道轴选择性。与自由基中心结合的取代基或与自由基中心结合的轴向取代基导致轴向侵蚀增加。赤道/3-取代基或轴向β-取代基增加赤道攻击的量。卤素和夺氢反应也观察到相同的趋势;轴向反应产物的量通常略高于加成反应。立体选择性可以用空间和扭转效应来解释,这与环己酮的亲核加成反应所建议的非常相似。