Generation of Sulfonyl Radicals from Aryldiazonium Tetrafluoroborates and Sulfur Dioxide: The Synthesis of 3-Sulfonated Coumarins

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• 作者：Danqing Zheng ; Jiyao Yu and Prof. Dr. Jie Wu
• 刊名：Angewandte Chemie
• 出版年：2016
• 出版时间：September 19, 2016
• 年：2016
• 卷：128
• 期：39
• 页码：12104-12108
• 全文大小：538K
• ISSN：1521-3757

文摘

A catalyst-free approach for the generation of sulfonyl radicals from aryldiazonium tetrafluoroborates in the presence of DABCO⋅(SO₂)₂ is realized. The combination of aryldiazonium tetrafluoroborates, DABCO⋅(SO₂)₂, and aryl propiolates affords 3-sulfonated coumarins in good to excellent yields. This tandem reaction process involves radical addition, spirocyclization, and 1,2-migration of esters. Additionally, the in situ diazotization of a number of anilines allows the directional synthesis of desired 3-sulfonated coumarins in a one-pot, two-step process.