Nitronate Anion Recognition and Modulation of Ambident Reactivity by Hydrogen-Bonding Receptors
作者:Brian R. Linton、M. Scott Goodman、Andrew D. Hamilton
DOI:10.1002/1521-3765(20000703)6:13<2449::aid-chem2449>3.0.co;2-9
日期:2000.7.3
resulted in a change in the ambident reactivity during alkylation with p-nitrobenzyl bromide. The predominant reaction pathway was shifted from oxygen alkylation to carbon alkylation as receptor binding strength increased. Kinetic analysis indicated an overall inhibition of nitronate reactivity, and this suggests that greater suppression of the oxygen pathway allows carbon alkylation to predominate.
硝酸根阴离子在DMSO中与氢键受体(例如1,3-二甲基硫脲1(K(a)= 120M(-1))和双环胍2(K(a)= 3200M(-1)))形成络合物。 。双位双硫脲显示与底物的缔合增加,底物含有两个硝酸盐(K(a)= 7000M(-1))或硝酸盐和羧酸盐的组合(K(a)= 7200M(-1))。在用对硝基苄基溴烷基化的过程中,硝酸盐的络合导致环境反应性的变化。随着受体结合强度的增加,主要的反应途径从氧烷基化转变为碳烷基化。动力学分析表明总体上抑制了硝酸盐反应性,这表明更大程度地抑制氧途径使碳烷基化占主导。