Anti‐Selective Carbosilylation: Nickel‐Catalyzed Multicomponent Reaction of Solid Me3SiZnI

Abstract

AbstractThe stereodefined and highly substituted vinylsilanes are essential building blocks for constructing complex organic molecules. Transition metal‐mediated silylmetalation of alkynes was developed to overcome the limitations of conventional hydrosilylations; however, a very limited study was carried out to utilize transient vinylmetal species in cross‐coupling reactions. Moreover, they produce syn‐adduct, and the anti‐selective cross‐coupling is still unknown and highly desired. Silylzinc reagents are highly functional group tolerant, however, their synthesis from pyrophoric silyllithium and dissolved lithium salts hampers cross‐coupling reactions. Our novel solid silylzinc reagents circumvent these constraints are employed in the anti‐selective synthesis of vinylsilanes via a multi‐component reaction involving Me3SiZnI, terminal alkynes, and activated alkyl halides. An intensive computational and experimental investigation of the mechanism reveals an equilibrium between the intermediate syn‐ and anti‐adducts; the greater barrier at the single electron reduction of alkyl halides and the thermodynamic stability of the Ni(III) adduct determine the anti‐selectivity.