Programmable Synthesis of Cationic Azaperylenes via Rh(III)-Catalyzed Multiple C–H/N–H Bonds Activation and Annulation

Rh(III)-catalyzed dual N–H and triple C–H activation/(4 + 2) annulation of 2-aryl-2,3-dihydro-1<i>H</i>-perimidines and alkynes has been disclosed to construct 4,5,14,15-tetrasubstituted cationic azaperylenes with high yields (up to 95%) and broad scope. Tandem (4 + 2) annulation of 1<i>H</i>-perimidines with vinylene carbonate and alkynes affords 4,5-disubstituted azaperylene salts, and <i>ortho</i>-alkynyl 1<i>H</i>-perimidines undergo an intra- and intermolecular annulation cascade to give 4,5,14-trisubstituted targets. Most of the intermediates were detected by ESI-MS, indicating a convincible mechanism including three possible paths. The resultant new cationic azaperylenes generally exhibit yellow to red emissions (540–642 nm), and the disubstituted cations exhibit longer emission wavelengths than their tri- and tetra-substituted partners. This protocol also offers a concise and efficient tool to construct perimidinium-based dications, showing potential applications in electrochromic devices.