Copper‐Catalyzed Difluoromethylation of β,γ‐Unsaturated Carboxylic Acids: An Efficient Allylic Difluoromethylation

Not one but two! A new strategy for the regiospecific construction of compounds with allylic CF2H groups has been developed. The decarboxylative (phenylsulfonyl)difluoromethylation of β,γ-unsaturated carboxylic acids is catalyzed by a Lewis acid (CuCl2⋅2 H2O), and the resulting product easily undergoes desulfonylation.