Carbon Cationic Relay via Superelectrophiles: Synthesis of Spiro‑diazafluorenes

Superelectrophilic-initiated
carbon cationic relay reactions of
diazafluorenones with phenols were developed to provide strategically
novel and atom-economic access to spirodiazafluorenes via tandem Friedel–Crafts
reaction, nucleophilic addition, and intramolecular cyclization sequences.
A range of spirodiazafluorenes that are difficult to synthesize with
traditional protocols has been constructed successfully in middle
to high yields using this method.