A series of six pharmaceutically promising 5,6-dihydro-11H-benzo[b][1]benzazepine derivatives (1c–h) were cleanly
prepared by Friedel–Crafts cyclialkylations of nitrogen-containing alkanols in the presence of AlCl3, 85% H2SO4 or
polyphosphoric acid catalysts. The precursor alkanols (13a–f) were readily prepared by reaction of two synthesized
carboxylic acid esters (12a, b) with different Grignard reagents. Also, two dibenzo[b,f]azepinones (15a, b) were prepared
by Friedel–Crafts cycliacylation and reduced to the corresponding 5,6-dihydro-11H-benzo[b][1]benzazepines (1a, b).
Overall, this approach allows easy and efficient access to polytricyclic amines from easily synthesized alkanols or
cycloketones. A plausible carbocation mechanism is proposed to account for the results.