Chiral cobalt(ii) complex catalyzed Friedel–Crafts aromatization for the synthesis of axially chiral biaryldiols

Abstract

An efficient atroposelective synthesis of axially chiral biaryldiols via asymmetric Friedel–Crafts aromatization between p-quinones and 2-naphthols was developed. A chiral cobalt(II) complex of N,N′-dioxide enabled the process to generate axially chiral biaryldiols in up to 98% yield and 95% ee. A large range of substituents at different positions of p-quinones and 2-naphthols was tolerable. The configuration of the product and the chiral N,N′-dioxide-Co(ClO₄)₂ catalyst was identified by X-ray crystal diffraction analysis and a possible catalytic model was suggested.