An efficient ecofriendly protocol for the synthesis of novel fluoro isoxazoline and isoxazolidines using N-benzyl fluoro nitrone via cycloaddition reactions

1-Butyl-3-methylimidazolium based ionic liquids are found to accelerate significantly the intermolecular 1,3-dipolar cycloaddition of N-benzyl fluoro nitrones derived in situ from aldehydes and benzylhydroxylamine, with electron deficient alkynes to afford enhanced rates and improved yields of isoxazolines while with enals exclusively endo isoxazolidines are obtained with high selectivity. Synthetic potentiality of the novel isoxazolines and nitrones has also been tested successfully.