Anionic Ligand Enabled Cobalt‐Catalyzed Hydrosilylation and Isomerization of Terminal Alkynes †

Comprehensive Summary Organosilicon compounds are widely valuable, making the efficient synthesis of alkenyl silanes an important research goal. A novel catalytic system based on a tridentate anionic ligand and cobalt has been developed for the Markovnikov‐selective hydrosilylation of terminal aliphatic alkynes, followed by isomerization of the disubstituted alkenyl silane intermediate, providing efficient access to trisubstituted alkenyl silanes. This system is also highly effective for the Markovnikov hydrosilylation of aryl alkynes. The protocol demonstrates broad functional group tolerance and can be performed on a gram scale. The catalyst achieves a turnover number (TON) of up to 1760 in hydrosilylation reaction. Mechanistic studies suggest that the anionic ligand, upon coordination, forms a dual functional catalyst with cobalt, which is key to enabling this transformation. It is proposed that a cobalt‐hydride species selectively catalyzes both the hydrosilylation of terminal alkynes and the subsequent isomerization of the disubstituted alkenyl silane. This work provides an efficient and selective synthetic method using an earth‐abundant metal catalyst for alkene synthesis via hydrosilylation and isomerization.