Nitrones and oxaziridines. XX. Intramolecular nitrone 1,3-dipolar cycloaddition by substituent interaction: Synthesis and reduction of some tetrahydropyrroloisoxazoles

Abstract

The reactions of C-benzoylnitrones with allylamine afford tetrahydro-5H-pyrrolo[3,4-c]isoxazoles resulting from imine formation and intramolecular 1,3-dipolar cycloadditions. Cycloaddition reactions of the same nitrones with 2-vinylpyridine and N-phenylallylamine afford 5-substituted isoxazolidines in the normal way. Reduction of the imine bond in the tetrahydropyrroloisoxazoles can be achieved by catalytic hydrogenation or sodium borohydride, and, in the case of an N-phenyl derivative, N-O bond cleavage also occurs.