Synthesis of Substituted Benzenes via Bi(OTf)₃‑Mediated Intramolecular Carbonyl Allylation of α‑Prenyl or α‑Geranyl β‑Arylketosulfones

Intramolecular carbonyl allylation of α-prenyl or α-geranyl β-arylketosulfones 5 in the presence of molecule sieves (MS) affords substituted benzenes 6–7 in moderate to good yields. The facile transformation proceeds by a synthetic sequence starting with the α-prenylation or α-geranylation of 1 and the Bi­(OTf)3-mediated annulation of 5 followed by a sequential desulfonative aromatization or then an intramolecular Friedel–Crafts alkylation. A plausible mechanism has been studied and proposed.