105924-81-0Relevant articles and documents
Nucleophilic substitution reactions of diethyl 4-nitrophenyl phosphate triester: Kinetics and mechanism
Castro, Enrique A.,Ugarte, Daniela,Rojas, M. Fernanda,Pavez, Paulina,Santos, Jose G.
, p. 708 - 714 (2011)
The reactions of diethyl 4-nitrophenyl phosphate (1) with a series of nucleophiles: phenoxides, secondary alicyclic (SA) amines, and pyridines are subjected to a kinetic study. Under excess of nucleophile, all the reactions obey pseudo-first-order kinetics and are first order in the nucleophile. The nucleophilic rate constants (kN) obtained are pH independent for all the reactions studied. The Bronsted-type plot (log kN vs. pKa nucleophile) obtained for the phenolysis is linear with slope β=0.21; no break was found at pKa 7.5, consistent with a concerted mechanism. The Bronsted-type plots for the SA aminolysis and pyridinolysis are linear with slopes β=0.39 and 0.43, respectively, also suggesting concerted processes. The concerted mechanisms for the latter reactions are proposed on the basis of the lack of break in the Bronsted-type plots and the instability of the hypothetical pentacoordinate intermediates formed in these reactions.
