Kinetics and mechanism of the aminolysis of aryl ethyl chloro and chlorothio phosphates with anilines

Title
Kinetics and mechanism of the aminolysis of aryl ethyl chloro and chlorothio phosphates with anilines
Authors
Ul Hoque, M.E.; Dey, N.K.; Kim, C.K.; Lee, B.S.; Lee, H.W .
Keywords
CROSS-INTERACTION CONSTANTS, METAL-ION CATALYSIS, PARA-NITROPHENYL DIPHENYLPHOSPHINATE
Issue Date
2007
Publisher
ROYAL SOC CHEMISTRY
Abstract
The reactions of ethyl Y-phenyl chloro ( 1) and chlorothio ( 2) phosphates with X-anilines in acetonitrile at 55.0 degrees C are studied kinetically and theoretically. Kinetic results yield the primary kinetic isotope effects (k(H)/k(D) = 1.07-1.80 and 1.06-1.27 for 1 and 2, respectively) with deuterated aniline (XC6H4ND2) nucleophiles, and the cross-interaction constants p(XY) = -0.60 and -0.28 for 1 and 2, respectively. A concerted mechanism involving a partial frontside attack through a hydrogen-bonded, four-center-type transition state is proposed. The large p(X)(p(nuc) = -3.1 to -3.4) and beta(X) (beta(nuc) = 1.1-1.2) values seem to be characteristic of the anilinolysis of phosphates and thiophosphates with the Cl leaving group. Because of the relatively large size of the aniline nucleophile, the degree of steric hindrance could be the decisive factor that determines the direction of the nucleophilic attack to the phosphate and thiophosphate substrates with the relatively small-sized Cl leaving group.
URI
http://dspace.inha.ac.kr/handle/10505/1896
Appears in Collections:
College of Natural Science(자연과학대학) > Chemistry (화학) > Journal Papers, Reports(화학 논문, 보고서)
Files in This Item:
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