Regiocontrol in the cobalt- catalyzed hydrosilylation of alkynes

Hydrofunctionalizations of unsaturated hydrocarbons are key strategies for the synthesis of functionalized building blocks. Here, we report highly versatile cobalt-catalyzed hydrosilylations of alkynes that operate with minute amounts of the inexpensive, bench-stable pre-catalyst Co(OAc)(2)4H(2)O under mild conditions (0.1-1 mol%, THF, r.t., 1 h). Near-perfect regiocontrol/stereocontrol was induced by the choice of the ligand: bidentate phosphines afforded (E)--vinylsilanes; -vinylsilanes formed with bipyridine ligands.