Exogenous Photosensitizer-, Metal-, and Base-Free Visible-Light-Promoted C–H Thiolation via Reverse Hydrogen Atom Transfer
作者:Ze-Ming Xu、Hong-Xi Li、David James Young、Da-Liang Zhu、Hai-Yan Li、Jian-Ping Lang
DOI:10.1021/acs.orglett.8b03679
日期:2019.1.4
This reaction induces the cyclization of thiobenzanilides to benzothiazoles. The substrate absorbs visible light, and its excited state undergoes a reverse hydrogen-atom transfer (RHAT) with 2,2,6,6-tetramethylpiperidine N-oxyl to form a sulfur radical. The addition of the sulfur radical to the benzene ring gives an aryl radical, which then rearomatizes to benzothiazole via RHAT.
无需添加光敏剂,金属催化剂或碱即可实现可见光驱动的分子内C(sp 2)–H硫醇化。该反应诱导了硫代苯甲酰胺环化为苯并噻唑。底物吸收可见光,并且其激发态与2,2,6,6-四甲基哌啶N-氧基发生反向氢原子转移(RHAT),形成硫自由基。硫自由基加到苯环上会得到一个芳基,然后再通过RHAT重新形成苯并噻唑。