Kinetics and mechanism of the anilinolysis of aryl phenyl isothiocyanophosphates in acetonitrile
作者:Hasi Rani Barai、Hai Whang Lee
DOI:10.3762/bjoc.9.68
日期:——
substituted X-anilines and deuterated X-anilines were carried out in acetonitrile at 55.0 degrees C. The free-energy relationships with X in the nucleophiles were biphasic concave upwards with a break region between X = H and 4-Cl, giving unusual positive rhoX and negative betaX values with less basic anilines (X = 4-Cl and 3-Cl). A stepwise mechanism with rate-limiting bond breaking for more basic anilines and
Y-芳基苯基异硫氰基磷酸酯与取代的 X-苯胺和氘代 X-苯胺的反应动力学研究在 55.0 摄氏度的乙腈中进行。亲核试剂中与 X 的自由能关系是双相向上凹,之间有一个断裂区域X = H 和 4-Cl,使用较少碱性苯胺(X = 4-Cl 和 3-Cl)给出不寻常的正 rhoX 和负 betaX 值。分别基于正和负的rhoXY 值,提出了一种逐步机制,对更多碱性苯胺进行限速键断裂,对较少碱性苯胺形成限速键。涉及氘代苯胺 (XC6H4ND2) 的氘动力学同位素效应显示出碱性较高和碱性较低的苯胺的主要正常和次要逆 DKIE,通过分别涉及氢键四中心型 TSf 和背面攻击 TSb 的正面攻击合理化。具有较少碱性苯胺的正 rhoX 值由紧密的 TS 证实,其中键形成的程度很大并且键断裂的程度相当小。