Enantioselective remote C-H activation directed by a chiral cation

Abstract

Chiral cations have been used extensively as organocatalysts, but their application to rendering transition metal-catalyzed processes enantioselective remains rare. This is despite the success of the analogous charge-inverted strategy in which cationic metal complexes are paired with chiral anions. We report here a strategy to render a common bipyridine ligand anionic and pair its iridium complexes with a chiral cation derived from quinine. We have applied these ion-paired complexes to long-range asymmetric induction in the desymmetrization of the geminal diaryl motif, located on a carbon or phosphorus center, by enantioselective C-H borylation. In principle, numerous common classes of ligand could likewise be amenable to this approach.