Easy access to β-halo amino esters and aziridine 2-carboxylic esters from halohydrins

The halohydrins prepared from epoxide esters, were treated with hydroxylamine derivatives. In subsequent reaction with NaOH/K2CO3/Bu4NHSO4 the N-protected β-halo α-aminoesters thus obtained were converted into N-hydroxy ariridine 2-carboxylic esters in good yields.