Hindered Nucleophilic Displacement (SN 2) Reactions of 2exo- and 2endo- Norbornyl Derivatives. Norbornane) Series 4
作者:Cyril A. Grob、Erich Lutz
DOI:10.1002/hlca.19810640115
日期:1981.2.4
exo-substitution products depends strongly on the base-nucleophile concentration. Ion pair intermediates are indicated. The extreme inertness of 2-norbornyl derivatives in displacement reactions is due to severe steric hindrance of rearside nucleophilic attack, a feature they have in common with other bi- and tricyclic molecules bearing nucleofugal groups adjacent to one or two bridgehead atoms.
在90%乙醇中的2个exo-和2个内-降冰片基溴化物(分别为1e和2e)与大量过量的氢氧化钾的反应,以及2个exo-降冰片基对甲苯磺酸盐(1g)与过量的硫代酚钠在甲基溶纤剂中的反应,已被研究。它们服从一阶速率定律,并且相对于碱基亲核试剂为零阶。但是,1,2-和1,3-消除与exo的比率-取代产物在很大程度上取决于碱基亲核试剂的浓度。标明了离子对中间体。2-降冰片基衍生物在置换反应中的极度惰性是由于背面亲核攻击的严重空间位阻,这是它们与带有一个或两个桥头原子的带有核真菌基团的其他双环和三环分子的共同特征。