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-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-perimidines with vinylene carbonate and alkynes affords 4,5-disubstituted azaperylene salts, and -alkynyl 1-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.