Construction of Nitrated Benzo[3.3.1]bicyclic Acetal/Ketal Core via Nitration of <i>o</i>‑Carbonyl Allylbenzenes

Intramolecular annulation of o-carbonyl allylbenzenes was achieved to construct novel nitrated [6,6,6]­tricycles having an acetal or ketal motif in good yields. The expeditious one-step nitration route provides 4 or 5 new bond formations, including 2 or 3 C–N bonds and 2 C–O bonds. The structural framework of benzobicycle [3.3.1] is confirmed by X-ray crystallographic analysis. A plausible mechanism is proposed.