Reductive and oxidative cleavage of 5-phenyl-Δ2-isoxazoline-3-carboxylic acid

The reductive cleavage of 5-phenyl-Δ2-isoxazoline-3-carboxylic acid (II; R = H) with zinc in acetic acid to give 4-phenyl-2-acetamido-γ-butyrolactone (III) is described. Oxidative fragmentation of the peroxy-esters t-butyl 5-phenyl-Δ2-isoxazoline-3-peroxycarboxylate (II; R = OBut) and t-butyl 5-phenylisoxazole-3-peroxycarboxylate (V; R = OBut) parallels the mass spectral fragmentation, to give benzaldehyde and 3-hydroxy-3-phenyl-propionitrile (VI), and 5-phenylisoxazole-3-carboxylic acid (V; R = H), respectively.