Bicyclic Bridgehead Phosphoramidite (Briphos) Ligands with Tunable π‑Acceptor Ability and Catalytic Activity in the Rhodium-Catalyzed Conjugate Additions

A new type of bicyclic bridgehead phosphoramidites (briphos) is reported, where the geometrical constraints significantly enhance the π-acceptor ability compared with its monocyclic analogs. The briphos is shown to be highly efficient and tunable for Rh­(I)-catalyzed conjugate additions of aryl boronic acids to α,β-unsaturated ketones and N-tosyl ketimines.