Lewis acid catalyzed intramolecular halo-arylation of tethered alkenes using N-halosuccinimide (NXS) as the halogen source: a general method for the synthesis of chromanones, chromans, quinolones, tetrahydroquinolines and tetralins

Lewis acid catalyzed intramolecular halo-arylation of tethered alkenes was performed using N-halosuccinimide (NXS) as the halogen source. Among the Lewis acids investigated, Sm(OTf)3 was found to be the best catalyst. This catalytic process provides a general method for the regio- and stereoselective synthesis of annulated arene heterocycles and carbocycles such as 2-chromanones, chromans, 2-quinolones, tetrahydroquinolines and tetralins possessing a halo-functionality.