Cobalt-Catalyzed AsymmetricSynthesis of Planar Chiral Ferrocene Derivatives via C(sp2)-C(sp3) Bond Formation

Transition -metal -catalyzed asymmetric C-H functionalization has developed into a powerful method for the facile synthesis of planar chiral ferrocene derivatives in recent decades. However, a large array of reactions in this category has been focused on enantioselective incorporation of an sp2 2 hybridized carbon -based functionality to the ferrocene backbone; meanwhile, successful examples on transition -metalcatalyzed asymmetric ferrocene C-H alkylation remain quite limited. Herein, we report an efficient synthesis of planar chiral ferrocene derivatives via Co -catalyzed C(sp2)-C(sp3) 2 )-C(sp 3 ) bond formation. Enabled by a binaphthyl-based chiral CpxCo x Co catalyst, ferrocene thioamides were readily coupled with allyl carbonates, delivering the corresponding planar chiral allylation products in up to 81% yield with 95% ee. Comprehensive mechanistic studies allowed the depiction of the kinetic profile, energy landscape of the reaction, the characterization of key CpxCo x Co complexes, and the establishment of the stereochemical model. The synthetic potential of this reaction was demonstrated by diverse transformations of the products and the preparation of new phosphine-olefin ligands for asymmetric (conjugated) addition reactions.