Construction of Vinyl-Substituted N-Heterocycles via Rh(III)- Catalyzed C-H Functionalization/Annulation of Pyrazolidinones

The transition-metal-catalyzed C-H activation and annulation reactions of pyrazolidinones with 4-vinyl-1,3-dioxolan-2-one or vinylene carbonate are described herein. This protocol provided two types of pyrazolo[1,2-a]cinnolines as essential assets for the development of bioactive compounds, and the synthetic practicality was performed and explained with 44 examples. The possible mechanism of these two reactions is proposed based on preliminary studies and previous reports, and no oxidant was added to both reactions.

Automated summary

This paper describes the transition-metal-catalyzed C-H activation and annulation reactions of pyrazolidinones with 4-vinyl-1,3-dioxolan-2-one or vinylene carbonate. This protocol provides two types of pyrazolo[1,2-a]cinnolines, which are essential assets for the development of bioactive compounds. The practicality of the synthesis is demonstrated with 44 examples, and a possible mechanism for these reactions is proposed based on preliminary studies and previous reports, with no oxidant added to both reactions.