525-530Microwave assisted
1,3-dipolar cycloaddition reaction of -chloro nitrones to novel -N-methyl and
-N-phenylfuran derivative affords exclusively single regioselective 5-spiro
isoxazolidines while the same reaction with -methylene--butyrolactone affords
two diastereomeric 5-spiro isoxazolidines with high selectivity