Hypervalent Iodine Reagent Mediated Oxidative Heterocyclization of Aldoximes with Heterocyclic Alkenes

An
efficient cycloaddition of heterocyclic alkenes with nitrile
oxides generated in situ from the corresponding aldoximes using organohypervalent
iodine­(III) reagent, [hydroxy­(tosyloxy)­iodo]­benzene (Koser’s
reagent), has been developed. The oxidative cyclization of various
aldoximes with 1-propene-1,3-sultone affords the respective isoxazoline-ring-fused
heterobicyclic products in moderate to good yields. Furthermore, the
reaction of aldoxime with a cyclic phospholene-oxide under similar
conditions produces the corresponding heterobicyclic phospholene oxides
in moderate yields. The structures of bicyclic phospholene oxide and
two sultones were established by single-crystal X-ray crystallography.