anion of benzaldehyde. The reaction through a six-membered transition state was modeled using density functional theory with the effect of solvent described by a polarized continuum model. The calculated secondary deuterium isotope effects based on this mechanism were found to be in good agreement with experimental values, thus adding further support to this mechanistic scenario.
一系列的段的烯丙基化巴尔比埃-使用竞争实验与烯丙基
溴在
锌,
铟,
锡,
锑,
铋,和Mg的存在取代的
苯甲醛进行了研究。在所有情况下,哈米特曲线的斜率都表明在选择性确定步骤中负电荷的积累。对于Zn,In,Sn,Sb和Bi,发现了反向的二次动力学同位素效应(k H / k D = 0.75-0.95),这与通过封闭的六价烯丙基化之前离散有机
金属物质的形成是相容的。过渡状态。使用
镁,负电荷的积聚明显更大,同时次级正动力学同位素效应也较小(k H / k D= 1.06)表明确定选择性的步骤是
苯甲醛自由基阴离子的产生。使用密度泛函理论对通过六元过渡态进行的反应进行建模,并用极化连续谱模型描述溶剂的作用。发现基于该机理计算出的次级
氘同位素效应与实验值非常吻合,从而为该机理提供了进一步的支持。