rate‐determining step. Comparison of the current kinetic data with those reported previously for the corresponding reactions with piperidine revealed that quinuclidine is ca. 102‐fold less reactive than piperidine. This is in contrast to the reports that quinuclidines are more reactive than isobasic secondary amines toward diaryl carbonates and related esters. Effects of amine nature on reactivity and TS structures
                                    在25.0±0.1°C下,用80 mol%H 2 O / 20 mol%
DMSO在20 mol%H 2 O / 20 mol%
DMSO中用分光光度法测定了Y-取代的苯基
吡啶甲酸(7a-7i)与一系列
奎尼丁的反应的二级速率常数(k N)。。用于反应中的布朗斯台德型情节7A-7I与
奎宁环是具有线性β LG  = -0.80。汤川-津野情节表现出与ρ优异的线性相关Ŷ  = 2.37和- [R  = 0.52,表明负电荷部分地开发在离去基团中的速率决定过渡态(
TS)O原子。2-
氯-4-
硝基苯基
吡啶甲酸(7a)反应的Brønsted型图 )用一系列
奎宁环的也是线性的与β NUC  = 0.83。因此,可以得出结论,反应是通过逐步机制进行的,其中在速率确定步骤中发生了离去基团的驱逐。将当前动力学数据与先前报道的与
哌啶的相应反应的动力学数据进行比较,发现
奎尼丁为约。反应活性比
哌啶低10 2倍。与之相反的