C–H/N–H Annulation of <i>N</i>‑Aryl Triazolinediones with Diazo Compounds: A Route to Cinnoline Analogues

The preparation and functionalization of cinnolinones and dihydrocinnolinones have emerged as important topics in medicinal chemistry and drug discovery. In this study, we report an iridium(III)-catalyzed C–H/N–H annulation between N-aryl triazolinediones and diazo Meldrum’s acid to access a range of dihydrocinnolinones. Furthermore, by modulation of the reaction conditions, a ruthenium(II)-catalyzed annulative cyclization of N-aryl triazolinediones with α-diazo-β-ketoesters was developed to efficiently produce cinnolines.