Visible‐Light Photoredox‐Catalyzed Decarboxylative Double Difluoromethylation of β,γ‐Unsaturated Carboxylic Acids for the Synthesis of Difluoromethylated Allylic Compounds

The regioselective synthesis of double difluoromethylated allylic products from easily accessible β,γ‐unsaturated carboxylic acids and difluoromethylation reagents under visible‐light photocatalysis is reported. This transformation tolerates various bromodifluoroacetates and fluorinated phosphonates, providing access to various difluoromethylated allylic products in 54–93% yield with 80:20 to 99:1 Z/E, which can not be readily synthesized using the currently known methods. Choosing fac‐[Ir(ppy)3] as the photocatalyst and 1,4‐diazabicyclo[2.2.2]octane (DABCO) as the additive is crucial for the success of this transformation.