Access to Difluoromethylated Arenes by Pd-Catalyzed Reaction of Arylboronic Acids with Bromodifluoroacetate

An unprecedented example of Pd-catalyzed difluoromethylation of aryl boronic acids with bromodifluoroacetate is described. The reaction proceeds under mild reaction conditions with hydroquinone and Fe(acac)3 as additives. Preliminary mechanistic studies reveal that a difluorocarbene pathway is involved in the reaction, which is unusual compared to the most traditional approaches. This reaction has advantages of high efficiency and excellent functional group compatibility, even toward bromide and hydroxy group, thus providing a useful protocol for drug discovery and development.