Trimethylenemethane Derivatives Stabilized by Conjugation II − Concerted or Nonconcerted Generation?
作者:Wolfgang R. Roth、Holger Wildt、Andreas Schlemenat
DOI:10.1002/1099-0690(200111)2001:21<4081::aid-ejoc4081>3.0.co;2-#
日期:2001.11
in a nonconcerted fashion, from the bicyclic methylenecyclopropanes 26, 30, 33, and 40, through the planar diradicals 28, 31, 35, and 50, respectively. The different reaction modes are viewed as being caused by the different coupling probabilities of the underlying vibrations. The orthogonal or planar geometries of the diradicals were derived from stereochemical and kinetic arguments. Additional thermodynamic
协同形成正交三亚甲基-双自由基型的3,6,和12已被证明为三个homofulvenes 2,4,和7,并显示出在一个对旋方式优先进行。相同类型的正交二价基团的形成,但在一个nonconcerted方式,从双环亚甲基环26,30,33,和40,穿过平面二价基团28,31,35,和50, 分别。不同的反应模式被认为是由基础振动的不同耦合概率引起的。双基的正交或平面几何形状是从立体化学和动力学论证中得出的。通过氧俘获实验,对三个双自由基[ 3c,(E)-19和41 ]进行了额外的热力学表征。