Programmable\nSynthesis of Cationic Azaperylenes via\nRh(III)-Catalyzed Multiple C–H/N–H Bonds Activation\nand Annulation

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