Kinetics and mechanism of the anilinolysis of dimethyl and diethyl chloro(thiono)phosphates

Abstract

Abstract The deuterium kinetic isotope effects (KIEs) involving deuterated aniline nucleophiles (XC 6 H 4 ND 2 ) are reported for the reactions of dimethyl chlorophosphate ( 1 ), dimethyl chlorothionophosphate ( 2 ), diethyl chlorophosphate ( 3 ) and diethyl chlorothionophosphate ( 4 ) in acetonitrile at 55.0 °C. The obtained k H / k D values are 0.798–0.979, 0.945–1.06, 0.714–0.919 and 1.01–1.10 for 1 , 2 , 3 and 4 , respectively. A concerted mechanism with dominant backside nucleophilic attack is proposed for the reactions of 1 and 3 . A concerted mechanism involving partial frontside attack through a hydrogen‐bonded four‐centre‐type transition state (TS) is proposed for the reactions of 2 and 4 . Copyright © 2008 John Wiley & Sons, Ltd.