857641-39-5Relevant articles and documents
Kinetic study on nucleophilic substitution reactions of 4-Nitrophenyl X-Substituted-2-Methylbenzoates with cyclic secondary amines in acetonitrile: Reaction mechanism and failure of reactivity-selectivity principle
Lee, Ji-Youn,Kim, Min-Young,Um, Ik-Hwan
, p. 93 - 97 (2014/02/14)
A kinetic study is reported on nucleophilic substitution reactions of 4-nitrophenyl X-substituted-2-methylbenzoates (5a-e) with a series of cyclic secondary amines in MeCN at 25.0 ± 0.1 °C. The Hammett plots for the aminolysis of 5a-e are nonlinear, e.g., substrates possessing an electron-donating group (EDG) in the benzoyl moiety deviate negatively from the linear line composed of substrates bearing no EDG. In contrast, the Yukawa-Tsuno plots for the same reactions exhibit excellent linear correlations with pX = 0.30-0.59 and r = 0.90-1.15, indicating that the nonlinear Hammett plots are caused by stabilization of the substrates possessing an EDG through resonance interactions but are not due to a change in the rate-determining step (RDS). The Bronsted-type plots are linear with βnuc = 0.66-0.82. Thus, the aminolysis of 5a-e has been suggested to proceed through a stepwise mechanism in which departure of the leaving group occurs at the RDS. The PX and βnuc values for the aminolysis of 5a-e increase as the reactivity of the substrates and amines increases, indicating that the reactivity-selectivity principle is not applicable to the current reactions.
