Evaluation of <i>e</i><i>xo</i>-<i>e</i><i>ndo</i> Ratios in the Halolactonization of ω-Unsaturated Acids
作者:Marie-Claude Roux、Renée Paugam、Gérard Rousseau
DOI:10.1021/jo0017234
日期:2001.6.1
competition between electronic and steric effects. These latter were developed by transannular interactions (for the acid chain lengths 8-11) and/or the conformations adopted by the chains (for the acid chain lengths > or = 14,) which disfavored the formation of the exo lactones. The larger proportion of endo lactones observed with the bromo reagent compared to the iodo reagent seemed due to electronic factors
考察了2-(ω-烯基)苯甲酸与双(可力丁)碘和双(可力丁)溴六氟磷酸盐的反应。除了仅获得外泌内酯的2-丁-3-烯基苯甲酸外,对于其他酸,总是得到外泌内酯的混合物。内酯的比例对于11个碳原子的酸链长度(形成12元环内酯)和高于14个碳原子的酸链长度都很重要。在分子计算的基础上,通过电子和空间效应之间的竞争解释了内酯的形成。后者是通过跨环相互作用(对于酸链长度为8-11)和/或由链采用的构象(对于酸链长度>或= 14)形成的,这不利于外泌内酯的形成。