Indium(III) triflate-catalyzed reaction of 2-carbomethoxycyclobutanone with nitrones

Abstract 2-Carbomethoxycyclobutanone reacted with N -phenyl- C -arylnitrones to afford methyl 5-oxo-2-[aryl(phenylamino)methyl]tetrahydrofuran-2-carboxylates by the catalysis of indium(III) triflate in the presence of magnesium sulfate.