Synthesis of 4H-chromene-3-carbaldehydes via ring-opening of gem-dichlorocyclopropane-fused 4H-chromenes

4H-Chromene-3-carbaldehydes were obtained via ringopening of gem-dichlorocyclopropane-fused 4H-chromenes upon treatment with silver or sodium acetates in boiling acetic acid. This transformation proceeds efficiently (up to 88% yield) and represents a rare example for the conversion of 1,1-dihalocyclopropanes into α,β-enals. The reaction tolerates a range of (hetero)aryl substituents and is applicable to both chromene and benzochromene scaffolds.