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.

The Rh(III)‐catalyzed C−H annulation reactions of N‐aryl indazolones or N‐aryl phthalazinones with a vinylene carbonate is described herein. This transformation provides the rapid access to indazolocinnolines and phthalazinocinnolines as important assets towards the development of novel bioactive compounds. Intriguingly, a vinylene carbonate acts as a vinyl transfer agent to enable the [4+2] annulation reaction. This method is characterized by its simplicity, mild reaction conditions, and broad functional group tolerance.

The ruthenium(II)-catalyzed cross-coupling reaction between 2-aryl quinazolinones and activated aldehydes is described. The method enables the site‐selective hydroxyalkylation under redox-neutral conditions. Moreover, this protocol provides a facile access to various...