Transition-State Variation in the Nucleophilic Substitution Reactions of Aryl Bis(4-methoxyphenyl) Phosphates with Pyridines in Acetonitrile
作者:Hai Whang Lee、Arun Kanti Guha、Chang Kon Kim、Ikchoon Lee
DOI:10.1021/jo0162742
日期:2002.4.1
The kinetics and mechanism of the reactions of Z-aryl bis(4-methoxyphenyl) phosphates, (4-MeOC(6)H(4)O)(2)P(=O)OC(6)H(4)Z, with pyridines (XC(5)H(4)N) are investigated in acetonitrile at 55.0 degrees C. In the case of more basic phenolate leaving groups (Z = 4-Cl, 3-CN), the magnitudes of beta(X) (beta(nuc)) and beta(Z) (beta(lg)) indicate that mechanism changes from a concerted process (beta(X) =