Ruthenium-catalyzed synthesis of quinolines from anilines and N-allylic compounds by cascade amine exchange reaction-heteroannulation

Anilines react with N-allylic compounds such as triallylamine and N,N-diall ylaniline in dioxane in the presence of a catalytic amount of ruthenium(III ) chloride hydrate and bis(diphenylphosphino)methane and tin(II) chloride d ihydrate to afford the corresponding quinolines in high yields. Several oth er phosphorus ligands are also effective, but bis(diphenylphosphino)methane is the ligand of choice. A reaction path way involving cascade amine excha nge reaction-heteroannulation is proposed for this catalytic process.