Asymmetric ruthenium-catalyzed hydrogenation of 2,6-disubstituted 1,5-naphthyridines: access to chiral 1,5-diaza-cis-decalins

Abstract

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.

Keywords: asymmetric catalysis; enantioselectivity; heterocycles; hydrogenation; ruthenium.