Synthesis of 2′,3′,4′-triaryl-5,6-dihydro-8H-spiro[indolizine-7,5′-isoxazolidin]-8-ones via 1,3-dipolar cycloaddition reaction involving (Z)-C-aryl-N-phenylnitrones

The 1,3-dipolar cycloaddition of C-aryl-N-phenylnitrones to 7-arylmethylidene-6,7-dihydroindolizin-8(5H)-ones afforded novel 2',3',4'-triaryl-5,6-dihydro-8H-spiro[indolizine-7,5'-isoxazolidin]-8-ones in moderate yields. The structures of all the products were proved by NMR and IR spectroscopy, HRMS, and X-ray analysis.