Radical Addition of Hydrazones by α-Bromo Ketones To Prepare 1,3,5-Trisubstituted Pyrazoles via Visible Light Catalysis
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- 作者：Xiu-Wei Fan ; Tao Lei ; Chao Zhou ; Qing-Yuan Meng ; Bin Chen ; Chen-Ho Tung ; Li-Zhu Wu
- 刊名：Journal of Organic Chemistry
- 出版年：2016
- 出版时间：August 19, 2016
- 年：2016
- 卷：81
- 期：16
- 页码：7127-7133
- 全文大小：446K
- 年卷期：0
- ISSN：1520-6904
文摘
A novel efficient tandem reaction of hydrazones and α-bromo ketones is reported for the preparation of 1,3,5-trisubstituted pyrazoles by visible light catalysis. In this system, the monosubstituted hydrazones show wonderful reaction activity with alkyl radicals, generated from α-bromo ketones. A radical addition followed by intramolecular cyclization affords the important pyrazole skeleton in good to excellent yields. This efficient strategy under mild conditions with wide group tolerance provides a potential approach to the 1,3,5-trisubstituted pyrazoles.