A reaction mixture of β,γ-unsaturatedketone and BF 3 .OEt 2 in CH 3 OH was stirred at room temperature and β-methoxy ketone was produced in high yield. The β-amino ketone was obtained as the major product from a reaction mixture of β,γ-unsaturatedketone, AlCl 3 and Ts-NH 2 in CH 2 Cl 2 at room temperature. This Lewis acid promoted β-substitution reaction mechanism was proposed as that the process