Cobalt-Catalyzed Chemoselective and Divergent Synthesis of 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.