Asymmetric Nickel-Catalyzed Hydrocyanation of Vinylarenes by Applying Homochiral Xantphos Ligands

New homochiral xantphos‐type diphosphonite ligands with binaphthoxy substituents have been prepared and characterized by NMR spectroscopy. These ligands have been applied in the nickel‐catalyzed hydrocyanation of styrene and other vinylarenes. Enantioselectivities up to 63 % ee have been obtained by using 4‐isobutylstyrene as a substrate. Addition of an excess of ligand strongly inhibits the hydrocyanation reaction since the bis‐chelate nickel complexes formed are highly stable and catalytically inactive. Enantioselectivities of up to 63 % were achieved in the hydrocyanation of vinylarenes by using the very stable and selective nickel catalysts formed with the new chelating chiral diphosphonite ligands (e.g. see picture) described herein. Steric congestion in these ligands can prevent formation of inactive bis‐chelate complexes.