Transition metal salts-catalyzed aza-Michael reactions of enones with carbamates

[GRAPHIC] Several transition metal salts were found to catalyze aza-Michael reactions of enones with carbamates efficiently. The catalytic activity was strongly dependent on the nature of the metal salts. While conventional Lewis acids such as BF3.OEt2, AlCl3, or TiCl4 showed lower activity, group 7-11 transition metal salts in higher oxidation states such as ReCl5, Fe(ClO4)(3).9H(2)O, RuCl3.nH(2)O, OsCl3.3H(2)O, RhCl3.3H(2)O, lrCl(4).nH(2)O, PtCl4.5H(2)O or AuCl3.2H(2)O exhibited higher catalytic activity.