Difluorocarbene-Triggered Cyclization: Synthesis of (Hetero)arene-Fused 2,2-Difluoro-2,3-dihydrothiophenes.

An efficient method for the synthesis of (hetero)arene-fused 2,2-difluoro-2,3-dihydrothiophene derivatives using readily available sodium chlorodifluoroacetate (ClCF2CO2Na) has been developed. This transformation is achieved through a combination of a thiolate with difluorocarbene, followed by intramolecular nucleophilic addition to a ketone, cyano, or ester functional group.