Palladium-Catalyzed Negishi Cross-Coupling Reaction of Aryl Halides with (Difluoromethyl)zinc Reagent

The palladium-catalyzed
Negishi cross-coupling reaction of aryl
iodides and bromides with (difluoromethyl)zinc reagent bearing a diamine
such as TMEDA is achieved to provide the difluoromethylated aromatic
compounds in good to excellent yields. The advantages of (difluoromethyl)­zinc
reagent are that (1) the derivatives, which possess different stability
and reactivity, can be readily prepared via ligand screening and (2)
transmetalation of a difluoromethyl group from the zinc reagent to
palladium catalyst efficiently proceeds without an activator.