4, 5-Disubstituted 2-imino-1, 3-dioxolanes readily add to oxiranes in the presence of AlC13, furnishing 1, ao~-azolidin-2-ones in a stereospecific manner, where the configurations of oxiranes and iminodioxolanes are reaponsible for the configuration of products and the feasibility of the addition, respectively. A preliminary adduct, a spiro compound intermediate, is isolated, and its decomposition to oxazolidinone is demonstrated.
