Probing Persistent Intramolecular C−H···X (X = O, S, Br, Cl, and F) Bonding in Solution Using Benzyl Meldrum’s Acid Derivatives
作者:Eric Fillion、Ashraf Wilsily、Dan Fishlock
DOI:10.1021/jo802311w
日期:2009.2.6
Persistent intramolecular interactions between acidic C−H hydrogens and a variety of acceptors (X) (X = O, S, Br, Cl, and F) in solution were probed by 1H NMR experiments, using 5-benzyl Meldrum’s acid derivatives. To bring about formation of intramolecular C−H···X bonding, ortho-substituted benzyl Meldrum’s acids were designed, for which hydrogen bonding occurred through a six-membered ring. Introduction
酸性CHH氢与溶液中各种受体(X)(X = O,S,Br,Cl和F)之间的持久分子内相互作用通过1 H NMR实验使用5-苄基Meldrum的酸衍生物进行探测。为了形成分子内CH键·X键,设计了邻位取代的苄基麦德鲁姆酸,通过六元环进行氢键键合。在芳族部分上和在系链中引入取代基允许电子和空间因素的变化。麦德鲁姆酸的优越酸度影响了CH氢参与非经典CH-··X键的能力,并结合了空间位阻因子A 1,3,推动了苄基麦德鲁姆酸的构象性质。-烯丙基菌株。通过表征固态的苄基麦德鲁姆酸,通过X射线分析以及与溶液中观察到的相关构象,可以进一步了解分子内C-H···X键。