Development and Application of Chiral Binaphthyldimethyl η6-Benzene Ruthenium Catalysts

The development of effective chiral ligands is a central challenge in emerging asymmetric catalysis with chiral η6-benzene (Ben) metal complexes. Here, we present a novel class of binaphthyldimethyl Ben ligands, featuring a chiral binaphthyl scaffold linked to the η6-benzene coordination site by a methylene spacer. Despite the presence of multiple potential η6-binding sites, these ligands exhibit exclusive site-specific coordination to ruthenium (Ru), affording the desired chiral BenRuII catalysts. These catalysts enabled highly efficient phenol-directed asymmetric C–H activation of 1-aryl-2-naphthols with alkynes, providing rapid access to diverse chiral spirocycles bearing all-carbon quaternary stereocenters in excellent yields (up to 99%) and with high enantioselectivities (up to 97% ee).