Asymmetric Ruthenium-Catalyzed Hydrogenation of 2,6-Disubstituted 1,5-Naphthyridines: Access to Chiral 1,5-Diaza-cis-Decalins

The first asymmetric hydrogenation (AH) of 2,6-disubstituted and 2,3,6-trisubstituted 1,5-naphthyridines, catalyzed by chiral cationic ruthenium diamine complexes, has been developed. A wide range of 1,5-naphthyridine derivatives were efficiently hydrogenated to give 1,2,3,4-tetrahydro-1,5-naphthyridines with up to 99%ee and full conversions. This facile and green protocol is applicable to the scaled-up synthesis of optically pure 1,5-diaza-cis-decalins, which have been used as rigid chelating diamine ligands for asymmetric synthesis.