Du Pan, Zhao Jiyang
School of Life Science and Chemistry, Jiangsu Second Normal University, Nanjing, 210013, China.
Office of Science and Technology, Nanjing Xiaozhuang University, Nanjing, 211171, China.
Chem Asian J. 2018 Mar 16;13(6):701-709. doi: 10.1002/asia.201701607. Epub 2018 Feb 28.
New methodology for the alkylation of amines is an intriguing issue in both academia and industry. Recently, several groups reported the metal-free B(C F ) -catalyzed N-alkylation of amines, but the mechanistic details of these important reactions are unclear. Herein, a computational study was performed to elucidate the mechanism of the N-alkylation of amines with formic acid catalyzed by the Lewis acid B(C F ) in the presence of hydrosilane. We found that the reaction started with the activation of formic acid through a novel model. Then, the high electrophilicity of the C center of the formic acid unit and the nucleophilic character of the amine resulted in a C-N coupling reaction. Finally, two sequential silyl-group and H transfer steps occurred to generate the final product. Upon comparing the reaction barrier and the hydrogenation of indole, our mechanism is more favorable than that proposed by the group of Yu and Fu.
胺烷基化的新方法在学术界和工业界都是一个引人关注的问题。最近，几个研究小组报道了无金属的B(CF)催化的胺N-烷基化反应，但这些重要反应的机理细节尚不清楚。在此，进行了一项计算研究，以阐明在硅烷存在下，路易斯酸B(CF)催化胺与甲酸进行N-烷基化反应的机理。我们发现，反应通过一种新型模型从甲酸的活化开始。然后，甲酸单元C中心的高亲电性与胺的亲核性导致了C-N偶联反应。最后，发生了两个连续的硅基和氢转移步骤，生成最终产物。通过比较反应势垒和吲哚的氢化反应，我们提出的机理比Yu和Fu小组提出的机理更有利。
