Rhodium-Catalyzed Carbon-Cyano Bond Cleavage Reactions Using Organosilicon Reagents

Rhodium-catalyzed carbon-cyano bond cleavage reactions using organosilicon reagents are described. When disilane is used as the silicon reagent, the C-CN bonds in aryl and alkenyl cyanides are silylated to form the corresponding silylated products along with silyl cyanide. Reductive decyanation of nitriles is achieved when hydrosilane is used as the silicon reagent. In addition, this catalytic system can be applied to the C(sp(3))-CN bonds in simple aliphatic nitriles. In both reactions, the silylrhodium species generated in situ serves as a catalytically active species, cleaving C-CN bonds via an eta(2)-iminoacyl complex. Addition of external electrophiles allowed the silicon-assisted cleavage of C-CN bonds to be applied to C-C bond formation reactions. Intramolecular arylation of benzonitrile bearing a tethered chlorophenyl group and decyanative Mizoroki-Heck-type alkenylation of nitriles with vinylsilanes have been developed.