Highly Chemo-, Regio-, and Stereoselective Cobalt-Catalyzed Markovnikov Hydrosilylation of Alkynes.

A highly chemo-, regio- and stereoselective cobalt-catalyzed Markovnikov hydrosilylation of alkynes was developed. Various functionalized groups, such as halides, free alcohols, free aniline, ketones, esters, amides, and nitriles are tolerated, which may lead to further applications and late-stage derivatizations. To date, this is the most efficient cobalt catalytic system (TOF=65 520 h(-1) ; TOF=turnover frequency) for hydrosilylation of alkynes. The Hiyama-Denmark cross-coupling reactions of vinylsilanes with aryl iodides underwent smoothly to afford 1,1-diarylethenes. A unique regioselectivity-controllable hydrosilylation/hydroboration reaction of alkynes was also described.