Herein, the use of a well-defined low-valent cobalt(I) catalyst [HCo(PMe3)4] capable of performing the highly regio- and stereoselective hydrosilylation of internal alkynes is reported. The reaction can be applied to a variety of hydrosilanes, symmetrical and unsymmetrical alkynes, giving in many cases a single hydrosilylation isomer. Experimental and theoretical studies suggest the key step to be a hydro-cobaltation and that the reaction proceeds through a classical Chalk-Harrod mechanism.

The use of a simple well-defined low-valent cobalt(I) catalyst [HCo(PMe3)4] capable of performing the regio- and stereoselective hydroboration of internal alkynes is reported. Extension to the diboration of internal alkynes is also related using the same reaction conditions.