Visible-Light Photocatalytic Aerobic Annulation for the Green Synthesis of Pyrazoles
Ya Ding, Te Zhang, Qiu-Yun Chen and Chunyin Zhu*
*School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, P. R. China, Email: zhucycngmail.com
Y. Ding, T. Zhang, Q.-Y. Chen, C. Zhu, Org. Lett., 2016, 18, 4206-4209.
DOI: 10.1021/acs.orglett.6b01867 (free Supporting Information)
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Visible light photoredox catalysis enables a selective and high yielding synthesis of polysubstituted pyrazoles in very good yields from hydrazine and various Michael acceptors under very mild reaction conditions in the presence of air as the terminal oxidant. The reaction is proposed to go through VLPC-promoted oxidation of hydrazine to diazene followed by its addition to Michael acceptors.
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