Controlled chemoselective defluorination and non-defluorination for [5 + 1] aromatic annulation via Meisenheimer-type nitrogen anion and radical intermediates† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c9sc03216a

A unique chemoselectivity to base-promoted defluorinative and Cu-catalyzed aerobic oxidative non-defluorinative [5 + 1] cycloaddition of fluoride unsaturated ketones with ammonium salts was demonstrated.
Reported is a unique chemoselectivity approach to base-promoted defluorinative and Cu(i)-catalyzed aerobic oxidative non-defluorinative [5 + 1] condensation aromatizations of simple unsaturated ketones with ammonium salts via Meisenheimer-type nitrogen anion and radical intermediates. The CuBr/O2 catalysis provides a straightforward approach to diverse 3-fluoropyridines in high yields. The synthetic utility of the strategy is highlighted by the concise synthesis of several F-modified bioactive compounds.