The kinetic studies on the pyridinolysis of diisopropyl thiophosphinic chloride have been carried out in acetonitrile at $55.0^\circ}C$. The free energy correlations for substituent X variations in the X-pyridines are biphasic concave upwards with a break point at X = 3-Ph. A concerted SN2 mechanism is proposed with a change of the attacking direction of the X-pyridine from a frontside attack for the strongly basic pyridines to a backside attack for the weakly basic pyridines. The factors to determine the rates and thio effects on the rates for the pyridinolyses of thiophophinic chloride, chlorothiophosphate, phosphinic chloride, phosphonochloridothioate, and chlorophosphate systems are briefly reviewed on the basis of the magnitude of the positive charge of the reaction center P atom and steric effects of the two ligands.
在
$55.0^\circ}C$的
乙腈中对
二异丙基硫代膦
氯化物的
吡啶解反应进行了动力学研究。 X-
吡啶中取代基 X 变化的自由能相关性是双相凹向上的,在 X = 3-Ph 处有一个断点。提出了一种协同的SN2机制,将X-
吡啶的攻击方向从强碱性
吡啶的正面攻击改变为弱碱性
吡啶的背面攻击。根据反应中心P原子正电荷的大小和空间位阻,简要综述了
硫代膦酰
氯、
氯硫代磷酸盐、次膦酰
氯、
硫代膦酰
氯和
氯磷酸盐体系
吡啶分解的速率决定因素以及
硫对速率的影响。两个
配体的作用。