Ruthenium-Catalyzed Synthesis of Quinolines from Anilines and Allylammonium Chlorides in an Aqueous Medium via Amine Exchange Reaction

Anilines react with allylammonium chlorides in an aqueous medium (H2O–dioxane) in the presence of a catalytic amount of RuCl2(PPh3)3 together with SnCl2·2H2O to give the corresponding quinolines in moderate to good yields. The existence of SnCl2·2H2O is necessary for the effective formation of quinolines, and a reaction pathway involving amine exchange reaction between anilines and allylammonium chlorides to form an imine is proposed for this catalytic process.