School of Chemistry and Chemical Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu, China.
Chemistry. 2010 Jan 4;16(1):248-53. doi: 10.1002/chem.200902132.
Competition experiments have been performed to determine the relative reactivities of substituted bromobenzenes and of different arylzinc reagents in the [Pd(PPh(3))(4)]-catalyzed Negishi cross-coupling reaction in THF at 25 degrees C. The cross-coupling reactions are accelerated by electron acceptors in the bromobenzenes, the effect of which increases in the order ortho <meta <para. On the other hand, electron acceptors in the arylzinc halides diminish the reaction rates. Hammett correlations show that substituent variations in the bromobenzenes (rho=+2.5) have a larger effect than substituent variations in the arylzinc halides (rho=-0.98).
已进行竞争实验以确定在 25°C 的 THF 中[Pd(PPh(3))(4)]催化的 Negishi 交叉偶联反应中取代的溴苯和不同芳基锌试剂的相对反应活性。溴苯中的电子受体加速了交叉偶联反应，其影响按邻位<间位<对位的顺序增加。另一方面，芳基锌卤化物中的电子受体降低了反应速率。Hammett 相关表明，溴苯中的取代基变化（rho=+2.5）的影响大于芳基锌卤化物中的取代基变化（rho=-0.98）。
