Palladium-catalyzed intramolecular diastereoselective dearomatization reaction of indoles with N-tosylhydrazones

A novel, highly diastereoselective palladium-catalyzed dearomative reaction of N-halobenzoyl o-haloaniline derivatives has been developed using functionalized N-tosylhydrazones as the coupling partners. This cascade dearomative protocol, which proceeds through sequential dearomative carbopalladation, migratory insertion, and β-hydride elimination, provides a reliable and straightforward access to a wide range of structurally diverse tetracyclic indolines with C2-quaternary stereocenters in moderate to good yields and excellent diastereoselectivities with good functional group compatibility.