Palladium-Catalyzed C-H Silylation through Palladacycles Generated from Aryl Halides.

A highly efficient palladium-catalyzed disilylation reaction of aryl halides through C-H activation has been developed for the first time. The reaction has broad substrate scope. A variety of aryl halides can be disilylated by three types of C-H activation, including C(sp2 )-H, C(sp3 )-H, and remote C-H activation. In particular, the reactions are also unusually efficient. The yields are essentially quantitative in many cases, even in the presence of less than 1 mol % catalyst and 1 equivalent of the silylating reagent under relatively mild conditions. The disilylated biphenyls can be converted into disiloxane-bridged biphenyls.