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Published on: July 17, 2020
Visible-Light-Induced Regioselective C(sp2)-H Radical Chlorination of Quinoxalin-2(1H)-ones with SOCl2-Pyridine
Rong Huang1, Zhenting Zhang1, Xia Zhao1
1College of Chemistry, Tianjin Key Laboratory of Structure and Performance for Functional Molecules, Key Laboratory of Inorganic-Organic Hybrid Functional Material Chemistry, Ministry of Education, Tianjin Normal University, Tianjin 300387, China.
Abstract:
Chlorination reactions serve as one of the most direct approaches for incorporating chlorine atoms into organic frameworks. Herein, we report a novel C(sp2)-H radical chlorination of quinoxalinones utilizing an SOCl2-pyridine system under visible-light irradiation at ambient temperature, without a photocatalyst. Mechanistic studies indicate that pyridinium salts formed from the reaction of SOCl2 with pyridine generate chlorine radicals via the formation of an electron donor-acceptor (EDA) complex with the substrate. The use of cost-effective reagents and mild reaction conditions makes this protocol an efficient and environmentally friendly method for C(sp2)-H chlorination.
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