Synthesis of 2,2-difluoro-2H-chromenes through the tandem reaction of ethyl 3-bromo-3,3-difluoropropionate with salicylaldehyde derivatives

A series of 2,2-difluoro-2H-chromenes were synthesized from the tandem reactions of ethyl 3-bromo-3,3-difluoropropionate with salicylaldehyde derivatives in good yields under basic conditions. In acidic environment defluorination took place during the reaction. A plausible mechanism was proposed based on the experimental results.