Addition of Carboxylic Acids to gem -Difluoroalkenes for the Synthesis of gem -Difluoromethylenated Compounds.

We herein describe a straightforward protocol for the synthesis of carboxylic esters containing a gem -difluoromethylene unit. Readily available carboxylic acids can act as nucleophiles to add regioselectively to tetrasubstituted or trisubstituted β,β-difluoroacrylates (formal hydroacetoxylation) for the construction of RCO 2 -CF 2 bonds. Thermal conditions are sufficient without the use of catalysts or additives.