Hou Zhong-Wei, Liu Ding-Jin, Xiong Peng, Lai Xiao-Li, Song Jinshuai, Xu Hai-Chao
Advanced Research Institute and Department of Chemistry, Taizhou University, Taizhou, 318000, P. R. China.
Laboratory of Chemical Biology of Fujian Province, State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China.
Angew Chem Int Ed Engl. 2021 Feb 8;60(6):2943-2947. doi: 10.1002/anie.202013478. Epub 2020 Dec 8.
C-H/N-H cross-coupling is an ideal strategy to synthesize various amines but remains challenging owing to the requirement for sacrificial chemical oxidants and the difficulty in controlling the regio- and chemo-selectivity. Herein we report a site-selective electrochemical amination reaction that can convert benzylic C-H bonds into C-N linkages via H evolution without need for external oxidants or metal catalysts. The synthetic strategy involves anodic cleavage of benzylic C-H to form a carbocation intermediate, which is then trapped with an amine nucleophile leading to C-N bond formation. Key to the success is to include HFIP as a co-solvent to modulate the oxidation potentials of the alkylbenzene substrate and the aminated product to avoid overoxidation of the latter.
C-H/N-H交叉偶联是合成各种胺类的理想策略，但由于需要牺牲性化学氧化剂以及难以控制区域和化学选择性，该方法仍然具有挑战性。在此，我们报道了一种位点选择性电化学胺化反应，该反应可通过析氢将苄基C-H键转化为C-N键，无需外部氧化剂或金属催化剂。该合成策略包括苄基C-H的阳极裂解以形成碳正离子中间体，然后该中间体与胺亲核试剂捕获，从而导致C-N键的形成。成功的关键是加入六氟异丙醇（HFIP）作为共溶剂，以调节烷基苯底物和胺化产物的氧化电位，避免后者的过度氧化。
