Mechanistic Insight into the Asymmetric N-H Insertion Catalyzed by Dirhodium Compound

• 作 者: QiaoXie;Li-PingGuo;Zhi-ZhongXie;
• 机 构: Department of Chemistry Wuhan University of Technology,Wuhan 430070
• 出 处: 第十二届全国量子化学会议
• 发表日期: 2014年期

　　The insertion of a carbenoid into N-H bond of an amine cooperatively catalyzed by a dirhodium catalyst has been investigated in detail using density functional theory methods.Calculations indicate that the reaction begins with the nucleophilic amine attack at the carbenoid to give a metal-associated ammonium ylide first followed by a rapid proton transfer to afford a metal-associated enamine intermediate.Subsequently the enamine intermediate can be dissociated from the metal.Formation of the enamine intermediate requires an overall barrier of 8.4 kcal/mol and remarkably exergonic by 12.2 kcal/mol.The conversion of the enamine into the N-H insertion product can be facilitated by the dirhodium catalyst through a two-step process,which has an activation free energy of 9.1 kcal/mol.