Annulative π-Extension by Ru(II)-Catalyzed <i>peri</i> -C–H Activation: Access to Pyranoacridine Photocatalyst

The precise construction of heteroatom-doped nanographenes remains a long-standing challenge in organic optoelectronics. Herein, we demonstrate a strategy for the synthesis of N,O-doped PAHs through Ru(II)-catalyzed peri-C–H activation/annulation of readily available acridones with internal alkynes. This protocol delivers diversely substituted pyranoacridines with high efficiency and excellent regioselectivity, as corroborated by DFT studies. Furthermore, this tetracyclic acridine core proved to be an efficient organo-photocatalyst for the dehalogenative reductive borylation and Truce–Smiles rearrangement of ortho-bromo benzanilides under visible-light irradiation.