Understanding the Unusual Regioselectivity in the Nucleophilic Ring-Opening Reactions of <i>g</i><i>em</i>-Disubstituted Cyclic Sulfates. Experimental and Theoretical Studies
作者:Alberto Avenoza、Jesús H. Busto、Francisco Corzana、José I. García、Jesús M. Peregrina
DOI:10.1021/jo034178q
日期:2003.5.1
The regioselectivity of the nucleophilic ring-opening reactions of three gem-disubstituted cyclic sulfates with sodium azide has been studied from both experimental and theoretical viewpoints. It is found that, depending on the substituent present in the cyclic sulfate, the reaction displays reversed regioselectivity, which allows one or another regioisomer to be obtained with selectivities greater
从实验和理论两个角度研究了三种宝石二取代的环状硫酸盐与叠氮化钠的亲核开环反应的区域选择性。已经发现,取决于环状硫酸盐中存在的取代基,该反应显示出反向的区域选择性,这使得可以以大于4:1的选择性获得一种或另一种区域异构体。理论计算表明,与以前的理解相反,在所有情况下,固有的偏好都是在取代度较低的Cβ位置发生叠氮化物攻击,这是所考虑的三种硫酸盐相似的立体电子效应的结果。对于硫酸酯而言,观察到的对Cα攻击的偏爱是通过不同的溶剂效应来解释的,