Abstract Novel β-hydroxy oxime O-ethers, as potential β-adrenergic blocking agents, were synthesized from the aqueous-mediated (H 2 O-DMSO, 7: 3) O-alkylation of oximes with epoxides in the presence of potassium hydroxide at room temperature. The O-alkylation was regioselective and (E)-oxime ethers were the main products. The results of quantum mechanical studies used to rationalize the experimental outcomes are discussed.