The synthesis and photochemical rearrangement chemistry of oxaziridnes derived from 3-benzyloxy- and 3-phenylcyclobutanone were examined. The oxaziridines were prepared by condensation of the ketones with α-methylbenzylamine followed by oxidation. Photolysis at 254 nm afforded good yields of readily separable lactams; 4-benzyloxy-pyrrolidin-2-one obtained in this way was converted to 4-amino-3-hydroxybutanoic acid (GABOB) by catalytic hydrogenolysis followed by acid hydrolysis.