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Kinetics and mechanism of the aminolysis of dimethyl and methyl phenyl phosphinic chlorides with anilines
Author(s) -
Dey Nilay Kumar,
Hoque Md. Ehtesham Ul,
Kim Chan Kyung,
Lee BonSu,
Lee Hai Whang
Publication year - 2009
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.1478
Subject(s) - chemistry , aminolysis , kinetic isotope effect , steric effects , nucleophile , deuterium , aniline , reactivity (psychology) , medicinal chemistry , acetonitrile , chloride , nucleophilic substitution , stereochemistry , organic chemistry , catalysis , medicine , physics , alternative medicine , quantum mechanics , pathology
The reactions of dimethyl phosphinic chloride ( 1 ) and methyl phenyl phosphinic chloride ( 2 ) with X‐anilines have been studied kinetically in acetonitrile at 15.0 and 55.0 °C, respectively. The deuterium kinetic isotope effects (KIEs) involving deuterated aniline nucleophiles (XC 6 H 4 ND 2 ) are also reported for the same reactions. The obtained KIEs for 1 are secondary inverse ( k H / k D = 0.703–0.899 < 1), while those for 2 are primary normal ( k H / k D = 1.62–2.10 > 1). A concerted mechanism involving predominantly backside nucleophilic attack is proposed for the anilinolysis of 1 . A concerted mechanism involving predominantly frontside attack via a hydrogen‐bonded four‐center‐type transition state is proposed for the anilinolysis of 2 . The degree of steric hindrance is the major factor that determines both the reactivity of the phosphinates and the direction of the nucleophilic attack on the phosphinates. Copyright © 2008 John Wiley & Sons, Ltd.