Chiral Binaphthol-Catalyzed Enantioselective Conjugate Addition of Alkynyl Trifluoroborates to α,β-Unsaturated Cyclic <i>N</i>-Sulfonyl Ketimines

The chiral binaphthol-catalyzed enantioselective conjugate addition of alkynyl trifluoroborates to cyclic <i>N-</i>sulfonyl ketimines is reported, providing β-alkynyl imines bearing a propargylic stereocenter in high yields and excellent enantiomeric purities (up to >99% <i>ee</i>). This mild, scalable catalytic system exhibits high efficiency and broad substrate scope. Additionally, heteroaryl trifluoroborates and aryl trifluoroborates were viable nucleophiles under standard conditions.