Several unsaturated sulfonamides underwent intramolecular aziridination when treated with PhI (OAc) 2, MgO, and catalytic Rh2 (OAc) 4 to give bicyclic aziridines in excellent yield. Treatment of the resulting azabicyclic sulfonamides in methanol in the presence of p-TsOH resulted in exclusive opening of the aziridine ring at the most substituted position affording six-and seven-membered ring products in high yield. In contrast, the intramolecular ...