Annulation of azobenzenes with vinylene carbonate for synthesis of (2H)-indazoles and dihydrocinnolinones via Rh(III)-catalysis
The Rh(III)-catalyzed C−H functionalization and subsequent intramolecular cyclization between azobenzenes and vinylene carbonate is described herein. Depending on the electronic property of azobenzenes, this transformation results in the formation of (2H)-indazoles or dihydrocinnolin-4-ones through the generation of ortho-alkylated azo-intermediates followed by decarboxylation. Surprisingly, vinylene carbonate acts as an acetaldehyde or acetyl surrogate to enable the [4+1] or [4+2] annulation reaction. This transformation is characterized by its mild reaction conditions, simplicity, and excellent functional group compatibility.
2024 Spring Convention