Cobalt-CatalyzedChemoselective and Divergent Synthesisof Vinylsilanes through Hydrosilylation of Acetylene

Vinylsilanes have significant value in organic synthesis, materials design, and organometallic chemistry. Compared to traditional methods for the synthesis of vinyl- or multivinylsilanes using dangerous multichlorosilanes and stoichiometric vinyl Grignard reagents, the earth-abundant transition-metal-catalyzed hydrosilylation of acetylene with multihydrosilane represents a more straightforward and atom-economical approach. However, selective and controllable acetylene hydrosilylation using multihydrosilanes is still challenging. Herein, we report a cobalt-catalyzed selective and controllable acetylene hydrosilylation with various hydrosilanes (including primary, secondary, and tertiary silanes). Mono-, bis-, trivinylsilane, or bis(silane)s are produced by a simple adjustment of the conditions. Both the reactivity and selectivity can be fine-tuned by changing the ligands, which allows for the highly selective and divergent synthesis of vinylsilanes. Detailed mechanistic studies indicate that the primary or secondary silane-assisted reduction of Co^II to produce an active low-valence Co^I intermediate is a prerequisite for the catalytic reaction. The Co^II reduction is also required for the reaction of the bulky and less reactive tertiary silanes. The obtained vinylsilanes and bis(silane)s have potential as silicon-containing monomers for the synthesis of organosilicon polymers.