A New Class of S<sub>N</sub>2 Reactions Catalyzed by Protic Solvents: Facile Fluorination for Isotopic Labeling of Diagnostic Molecules
作者:Dong Wook Kim、Doo-Sik Ahn、Young-Ho Oh、Sungyul Lee、Hee Seup Kil、Seung Jun Oh、Sang Ju Lee、Jae Seung Kim、Jin Sook Ryu、Dae Hyuk Moon、Dae Yoon Chi
DOI:10.1021/ja0646895
日期:2006.12.1
Aprotic solvents are usually preferred for the SN2 reactions, because nucleophilicity and hence SN2 reactivity are severely retarded by the influence of the partial positive charge of protic solvents. In this work, we introduce a remarkable effect of using tertiary alcohols as a reaction medium for nucleophilic fluorination with alkali metal fluorides. In this novel synthetic method, the nonpolar protic
SN2 反应通常优选非质子溶剂,因为质子溶剂的部分正电荷的影响严重阻碍了亲核性和 SN2 反应性。在这项工作中,我们介绍了使用叔醇作为碱金属氟化物亲核氟化反应介质的显着效果。在这种新的合成方法中,非极性质子叔醇在没有任何催化剂的情况下显着增强了氟离子的亲核性,大大提高了亲核氟化的速率并减少了副产物(如烯烃、醇或醚)与使用偶极非质子溶剂的常规方法相比。