Conversion of a nitrosocarbonyl hetero Diels-Alder cycloadduct to useful isoxazoline-carbocyclic aminols

A new approach to useful precursors for the synthesis of isoxazoline-carbocyclic nucleosides is detailed, starting from the readily available N-benzoyl-2,3-oxazanorborn-5-ene and introducing more polar and hydrophilic functionalities through 1,3-dipolar cycloaddition of carbethoxyformonitrile oxide, generated either from the corresponding hydroximoyl chloride or, more conveniently, by catalyzed condensation with ethyl nitroacetate.