Kinetics and Mechanism of the Addition of Benzylamines to Benzylidenemalononitriles in Acetonitrile
作者:Hyuck Keun Oh、Jin Hee Yang、Hai Whang Lee、Ikchoon Lee
DOI:10.1021/jo991823d
日期:2000.4.1
Nucleophilic addition reactions of benzylamines (BA) to benzylidenemalononitrile (BMN) have been studied in acetonitrile at 15.0 degrees C. The rate is first-order with respect to both BA and BMN and no base catalysis is observed. The rate decreases as the electron-withdrawing power of the substituent (Y) in the substrate increases (rho Y < 0). This is in contrast to the similar reactions of beta-nitrostyrenes
已在乙腈中于15.0摄氏度下研究了苄胺(BA)与亚苄基丙二腈(BMN)的亲核加成反应。相对于BA和BMN,该速率均为一级,并且未观察到碱催化。该速率随着基材中取代基(Y)的吸电子能力增加而降低(rho <0)。这与β-硝基苯乙烯(NS)与BA在乙腈中的相似反应以及NS和BMN在水溶液中的加成反应(rho Y> 0)相反。rho Y的这种符号变化被认为是由于BMN中(CN)2基团的强吸电子能力导致的,这导致过渡态的C alpha delta + C delta-(CN)2极化。乙腈中BMN胺加成的机理与水中的机理完全不同。