College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China.
Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen 518055, P. R. China.
J Org Chem. 2021 Sep 3;86(17):11905-11914. doi: 10.1021/acs.joc.1c01325. Epub 2021 Aug 3.
Aiming at the valuable methylation process, readily available and inexpensive ,,,-tetramethylethylenediamine (TMEDA) was first identified as a new methyl source in photoredox-catalyzed transformation in this work. By virtue of this simple methylating reagent, a facile and practical protocol for the direct C-H methylation of -heteroarenes was developed, featuring mild reaction conditions, broad substrate scope, and scalability. Mechanistic studies disclosed that a sequential photoredox, base-assisted proton shift, fragmentation, and tautomerization process was essentially involved.
针对有价值的甲基化过程，本工作首次鉴定出易得且廉价的四甲基乙二胺（TMEDA）可用作光氧化还原催化转化中的新型甲基源。借助这种简单的甲基化试剂，开发了一种用于 -杂芳环直接 C-H 甲基化的简便实用的方法，具有温和的反应条件、广泛的底物范围和可扩展性。机理研究表明，该过程涉及到一个连续的光氧化还原、碱辅助质子迁移、断裂和互变异构过程。
