Rhodium-catalyzed oxidative coupling between salicylaldehydes and internal alkynes with C-H bond cleavage to produce 2,3-disubstituted chromones

A direct oxidative coupling of salicylaldehydes with internal alkynes proceeds efficiently with cleavage of the aldehyde C-H bond to produce the corresponding chromone derivatives. A rhodium catalyst in combination with a cyclopentadiene ligand and a copper oxidant promote this straightforward annulation reaction. Solid-state luminescence was observed for certain chromone products.