Tian Jiaqi, Wang Gaobo, Qi Zheng-Hang, Ma Jing
School of Chemistry and Chemical Engineering, Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, Nanjing University, Nanjing 210093, People's Republic of China.
ACS Omega. 2020 Aug 21;5(34):21385-21391. doi: 10.1021/acsomega.0c01528. eCollection 2020 Sep 1.
The differences in catalytic activity between two catalyst ligands of Buchwald-Hartwig amination reaction, BrettPhos versus RuPhos, were investigated using density functional theory (DFT) calculations. The reaction process consists of three consecutive steps: (1) oxidative addition, (2) deprotonation, and (3) reductive elimination. Among them, the rate-limiting step of Pd-BrettPhos catalytic system is oxidative addition but that of Pd-RuPhos catalytic system is reductive elimination due to their differences in steric hindrance and electronic structure. It was also revealed that amines with large-size substituents or halides with electron-withdrawing groups would reduce the activation energy barriers of the reactions. The insights gained from the calculations of the Buchwald-Hartwig amination reaction would be helpful for the rational designing of new catalysts and reactions.
利用密度泛函理论（DFT）计算研究了布赫瓦尔德-哈特维希胺化反应的两种催化剂配体BrettPhos和RuPhos之间的催化活性差异。反应过程包括三个连续步骤：（1）氧化加成，（2）去质子化，以及（3）还原消除。其中，Pd-BrettPhos催化体系的速率限制步骤是氧化加成，而Pd-RuPhos催化体系的速率限制步骤是还原消除，这是由于它们在空间位阻和电子结构上的差异。研究还表明，具有大尺寸取代基的胺或具有吸电子基团的卤化物会降低反应的活化能垒。从布赫瓦尔德-哈特维希胺化反应计算中获得的见解将有助于合理设计新的催化剂和反应。
