An efficient and highly regioselective protocol was developed for the preparation of 5- hydroxy-2-isoxazolines, which have been proved to be versatile synthons for isoxazles, β- hydroxy oximes, and γ-amino alcohols. β-Lactams, commonly embedded in the skeletons of bioactive natural products, were also synthesized in two steps from β-hydroxy oximes, providing a new strategy for the synthesis of this kind of compounds.