Hydrodifluoromethylation of Alkenes with Difluoroacetic Acid.

A facile method for the regioselective hydrodifluoromethylation of alkenes is reported using difluoroacetic acid and phenyliodine(III) diacetate in tetrahydrofuran under visible-light activation. This metal-free approach stands out as it uses inexpensive reagents, does not require a photocatalyst, and displays broad functional group tolerance. The procedure is also operationally simple and scalable, and provides access in one step to high-value building blocks for application in medicinal chemistry.