Copper(I)‐Catalyzed Highly Regio‐ and Stereoselective Hydrosilylation of Terminal Alkynes with Boryldisiloxane

By employing 1,1,3,3‐tetramethyl‐1,3‐(pinacolboryl)disiloxane as a novel silicon source, the N‐heterocyclic carbene copper complex catalyzed hydrosilylation of terminal alkynes was developed to prepare vinyldisiloxanes in a highly regio‐ and stereoselective manner. A number of functional groups, including ether, ester, cyano, nitro, halo, hydroxyl, cyclopropyl, and aryl groups, were tolerated under the optimized conditions. A mechanistic investigation was undertaken by using density functional theory calculations. This approach allows facile entry to unsymmetrical disubstituted ( E )‐alkenes by Pd‐catalyzed cross‐coupling reactions.