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

Ze-Ming Xu, Hong-Xi Li*, David James Young, Da-Liang Zhu, Hai-Yan Li, Jian-Ping Lang*

*College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China, Email:

Z.-M. Xu, H.-X. Li, D. J. Young, D.-L. Zhu, H.-Y. Li, J.-P. Lang, Org. Lett., 2019, 21, 237-241.

DOI: 10.1021/acs.orglett.8b03679

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A visible-light-driven, intramolecular C(sp2)-H thiolation without addition of a photosensitizer, metal catalyst, or base induces the cyclization of thiobenzanilides to benzothiazoles. The substrate undergoes a reverse hydrogen-atom transfer (RHAT) in its excited state with TEMPO to form a sulfur radical, which adds to the benzene ring followed by a rearomatization via RHAT.

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proposed mechanism

Photocatalyst- and Transition-Metal-Free Visible-Light-Promoted Intramolecular C(sp2)-S Formation

H. Wang, Q. Wu, J.-D. Zhang, H.-Y. Li, H.-X. Li, Org. Lett., 2021, 23, 2078-2083.

Key Words

Benzothiazoles, Photochemistry, TEMPO

ID: J54-Y2019