concave upwards with a break point at X = H (2) and 3-Ph (4), respectively. A stepwise mechanism with a ratelimiting leaving group expulsion from the intermediate is proposed based on the magnitudes of selectivity parameters for both substrates. The considerably large values of βX = 1.50(2) and 1.44(4) with strongly basic pyridines and relatively small values of βX = 0.43(2) and 0.36(4) with weakly
在 X = H (2) 和 3-Ph (4) 处分别有一个断点向上凹。基于两种底物的选择性参数的大小,提出了一种具有限速离去基团从中间体排出的逐步机制。βX = 1.50(2) 和 1.44(4) 的相当大的值与强碱性
吡啶和相对较小的值 βX = 0.43(2) 和 0.36(4) 与弱碱性
吡啶被解释为攻击方向的变化X-
吡啶从正面到背面攻击
氯化物离去基团。