Exogenous Photosensitizer-, Metal-, and Base-Free Visible-Light-Promoted C–H Thiolation via Reverse Hydrogen Atom Transfer

Ze-Ming Xu^†, Hong-Xi Li^*†‡（李红喜）, David James Young^§, Da-Liang Zhu^†, Hai-Yan Li^†, and Jian-Ping Lang^*†‡（郎建平）

^†College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China

^‡State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China

^§College of Engineering, Information Technology and Environment, Charles Darwin University, Northern Territory 0909, Australia

Org. Lett., 2019, 21 (1), 237--241

Visible-light-driven, intramolecular C(sp²)–H thiolation has been achieved without addition of a photosensitizer, metal catalyst, or base. 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.

链接：https://pubs.acs.org.ccindex.cn/doi/10.1021/acs.orglett.8b03679