Synthesis of Pinpoint-Fluorinated Polycyclic Aromatic Hydrocarbons: Benzene Ring Extension Cycle Involving Microwave-Assisted SN Ar Reaction.

Fluoroarenes bearing no electron-withdrawing groups (non-activated fluoroarenes) readily underwent nucleophilic aromatic substitution with α-cyanocarbanions under microwave irradiation. The sequence (i) formylalkylation involving the cyanoalkylation of fluoroarenes, (ii) difluorovinylidenation, and (iii) Friedel-Crafts-type cyclization, afforded extended fluoroarenes by one benzene ring per cycle. Furthermore, the performance of multiple cycles successfully provided higher-order pinpoint-fluorinated polycyclic aromatic hydrocarbons (F-PAHs).