Catalytic Asymmetric Hydroalkenylation of Vinylarenes: Electronic Effects of Substrates and Chiral N‐Heterocyclic Carbene Ligands

Abstract

Abstract An asymmetric tail‐to‐tail cross‐hydroalkenylation of vinylarenes with terminal olefins was achieved by catalysis with NiH complexes bearing chiral N‐heterocyclic carbenes (NHCs). The reaction provides branched gem ‐disubstituted olefins with high enantioselectivity (up to 94 % ee ) and chemoselectivity (cross/homo product ratio: up to 99:1). Electronic effects of the substituents on the vinylarenes and on the N‐aryl groups of the NHC ligands, but not a π,π‐stacking mechanism, assist the steric effect and influence the outcome of the cross‐hydroalkenylation.