Enantioselective and Regioselective Hydroetherification of Alkynes by Gold-Catalyzed Desymmetrization of Prochiral Phenols with P-Stereogenic Centers

The gold(I)-catalyzed enantioselective hydroetherification of alkynes was achieved via desymmetrization of prochiral bisphenols bearing P-stereogenic centers. ( S)-DTBM-Segphos(AuCl)2/AgNTf2 proved to be a highly efficient catalyst system for this transformation, affording P-chiral cyclic phosphine oxides in good yields with high enantioselectivities (with up to 99% ee). The same catalyst system allowed for the enantioselective desymmetrization of dialkynes. Synthetic transformations of the cyclization products afforded other P-chiral molecules with high enantiospecificity.