Kinetics and Mechanism of the Addition of Anilines to beta-Nitrostilbenes in Acetonitrile

摘要

Addition reactions of anilines (XC6H4NH2) to beta-nitrostilbene (YC6H4CH=C(NO2)C6H4Y') have been investigated in acetonitrile at 30.0 °C.The magnitude of beta_x values (=0.11-0.34) indicates relatively earlier transition state for additions with anilines than with benzylamines.The signs of rho_Y and rho_Y are positive with DELTA rho = rho Y-rho Y = 0.04,demonstrating a TS imbalance with a negative charge development on the C_beta in the TS.The signs of cross-interaction constants rho xy (<0),rho xy' (<0) and rho yy' (>0) are consistent with bond forming and breaking processes.The relatively weak normal kinetic isotope effects involving deutarated nucleophiles,kH/KD>1,suggest an early,hydrogen-bonded,4-member cyclic TS.