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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 33, Number 8
BKCSDE 33(8)
August 20, 2012 

 
Title
Kinetics and Mechanism of the Anilinolysis of O-Ethyl Phenyl Phosphonochloridothioate in Acetonitrile
Author
Md. Ehtesham Ul Hoque, Hai Whang Lee*
Keywords
Phosphoryl transfer reaction, Anilinolysis, O-Ethyl phenyl phosphonochloridothioate, Deuterium kinetic isotope effect
Abstract
The nucleophilic substitution reactions of O-ethyl phenyl phosphonochloridothioate with substituted anilines (XC6H4NH2) and deuterated anilines (XC6H4ND2) are kinetically investigated in acetonitrile at 55.0 oC. The deuterium kinetic isotope effects (DKIEs) invariably increase from a secondary inverse DKIE (kH/kD = 0.93) to a primary normal DKIE (kH/kD = 1.28) as the substituent of nucleophile (X) changes from electron-donating to electron-withdrawing. These can be rationalized by the gradual transition state (TS) variation from a backside to frontside attack. A concerted SN2 mechanism is proposed. A trigonal bipyramidal TS is proposed for a backside attack while a hydrogen-bonded, four-center-type TS is proposed for a frontside attack.
Page
2707 - 2710
Full Text
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