An efficient access to substituted tetrahydroquinolines, benzo[b]azepines, pyrido[3,2,1-jk]carbazoles, benzo[kl]acridines and pyrido[3,2,1-de]acridines in overall very good yields is described. The process involves Friedel–Crafts cyclizations of homo-and heterocyclic carboxylic acids 1a-e and alkanols 3a-e in the presence of AlCl3/CH3NO2 or TfOH (trifluoromethanesulfonic acid) or polyphosphoric acid (PPA) under suitable reaction conditions. Starting carboxylic acids 1a-e were obtained from their literature procedures. Our simple strategy offers easy access to polycyclic-fused systems in short reaction times and in moderate to good yields.

Keywords: Friedel-Crafts cycliacylations; alkanols; pyrido[3,2,1-jk]carbazole; Grignard reactions;
benzo[kl]acridine