Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, California 95616, USA.
J Org Chem. 2011 Sep 2;76(17):7167-74. doi: 10.1021/jo2012175. Epub 2011 Aug 4.
Quantum chemical computations (B3LYP/6-31+G(d,p)) were applied to examine the mechanisms of dyotropic rearrangements of spirolactones in order to assess whether these reactions are concerted. Mechanistic experiments, designed on the basis of the results of these calculations, support the conclusions derived from theory. In particular, Zn(II) salts or Brønsted acids induce stepwise dyotropic processes, whereas dyotropic rearrangements mediated by silyltriflates are concerted processes. Additional products isolated with Zn(II) salts support a stepwise process with a carbocationic intermediate. Furthermore, a facile Grob-type fragmentation emanating from both a tricyclic-β-lactone and a spiro-γ-lactone was identified.
量子化学计算（B3LYP/6-31+G(d,p)）被应用于研究螺内酯的动态重排机制，以评估这些反应是否是协同的。基于这些计算结果设计的机理实验支持了从理论中得出的结论。特别是，Zn(II)盐或布朗斯台德酸诱导逐步动态重排过程，而由硅基三氟甲磺酸酯介导的动态重排是协同过程。与 Zn(II)盐分离得到的其他产物支持涉及碳正离子中间体的逐步过程。此外，还鉴定了源自三环-β-内酰胺和螺-γ-内酰胺的一种易发生的 Grob 型断裂。
