Synthesis of 4H‐Indazol‐4‐ones and Fused Pyrazoles via Copper‐Catalyzed Annulation of Hydrazones with Cyclic Enones

The copper-catalyzed annulation reaction between hydrazones and cyclic enones (5-, 6-, and 7- membered) affords diversely functionalized fused pyrazoles. These molecular scaffolds have been further functionalized successfully.

Abstract

Herein, we report the synthesis of cyclic ketone-fused pyrazoles via [3+2] annulation reaction between hydrazones and cyclic enones (five-, six- and seven-membered) catalyzed by Cu(II) under aerobic conditions. These compounds were further functionalized by reactions such as Suzuki-Miyaura cross-coupling, Heck coupling, and Aldol reaction to afford diverse molecular scaffolds in good yield, selectivity and functional group tolerance.

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