Enantioselective Pericyclization of Naphthol-Substituted Alkynyl Ketimines

A vinylidene ortho-quinone methide (VQM)-mediated, organocatalyzed tandem 6π-azaelectrocyclization and dearomatizing spirocycloaddition of naphthol-substituted alkynyl ketimines, facilitated by NBS, have been realized. This strategy enables the enantioselective synthesis of axially chiral 3-haloquinolines and previously unexplored spirocyclic xanthenopyrroles under mild conditions, with excellent functional group tolerance and high efficiency. Significantly, this represents the first intramolecular method for constructing axially chiral biaryl quinolines via 6π-azaelectrocyclization of naphthol-substituted alkynyl ketimines. Furthermore, a range of downstream transformations highlights the broad synthetic utility of these halogenated heterobiaryls.