Treatment of N-[2-(3, 4-dimethoxyphenyl) ethyl]-α-(methylthio) acetamide 3 with Mn (OAc) 3 in the presence of Cu (OAc) 2 gave tetrahydroindol-2-one 4, which then cyclized with Mn (OAc) 3 to give 4-acetoxyerythrinane 5. A similar reaction of the 3, 4-methylenedioxyphenyl congener 8 also gave tetrahydroindol-2-one 9, which, however, gave only a trace amount of the Mn (OAc) 3-mediated cyclization product 11 and afforded the oxidation product 10. On ...