Defluorinative Approach for the Synthesis of Chromones via [4 + 2] Annulation of Difluoro Quinone Methide

We have developed a transition metal-free defluorinative method for 2-(trifluoromethyl)phenol, which facilitates the synthesis of chromones. This reaction features a previously unexplored [4 + 2] annulation of in situ-generated reactive difluoro quinone methide and 1,3-dicarbonyl compounds. Notably, this distinct mode of reactivity applies to a diverse array of substrates and operates under mild conditions, showcasing scalability.