Lewis acid catalyzed formation of 3-amino-3-carboxy-tetrahydroquinoline derivatives via tandem 1,5-hydride transfer/cyclization process

A Sc(OTf)3-catalyzed intramolecular tandem 1,5-hydride transfer/cyclization process to construct 3-amino-3-carboxy-tetrahydroquinoline derivatives has been developed. The methodology gives access to a range of relatively complex tetrahydroquinolines (tetracyclic and pentacyclic heterocycles bearing spirocyclic skeleton and two stereogenic centers) in good to excellent yields with diastereoselectivities ranging from 57:43 to 73:27. The synthetic utility of the method was also demonstrated by an efficient ring opening derivatization reaction.