Base-Free Dehydrogenative Coupling of Enolizable Carbonyl Compounds with Silanes

A dehydrogenative coupling between enolizable carbonyl compounds and equimolar amounts of triorganosilanes catalyzed by a tethered ruthenium complex with a Ru-S bond is reported. The complex is assumed to fulfill a dual role by activating the Si-H bond to release a silicon electrophile and by abstracting an α-proton from the intermediate silylcarboxonium ion, only liberating dihydrogen as the sole byproduct. Reaction rates are exceedingly high at room temperature with very low loadings of the ruthenium catalyst.