The Triflic Acid-Mediated Cyclization Reactions of N‑Cinnamoyl-1-Naphthylamines

N-Cinnamoyl-1-naphthylamines undergo a cyclization reaction with triflic acid to form 4-phenyl-3,4-dihydro-1H-naphth­[1,8-bc]­azepin-2-ones and 4-phenyl-3,4-dihydro-1H-benzo­[h]­quinolin-2-ones. However, the N-benzyl analogues also undergo a unique cascade reaction to form novel heptacyclic structures via a 1,2-addition followed by a 4-addition to the naphthalene. With an electron-rich N-benzyl substituent, the heptacycle is the sole product.