Abstract Alkylation of 2-substituted (4 S, 5 S)-4, 5-bis (hydroxymethyl)-1, 3-dioxolanes with 9- benzyl-1, 17-diiodo-3, 6, 12, 15-tetraoxa-9-azaheptadecane afforded new chiral aza and diaza crown ethers as a result of [1+ 1] and [2+ 2] additions. Their catalytic debenzylation gave the corresponding derivatives with a secondary amino group. The reaction of diethyl (+)-tartrate and diethyl (4 S, 5 S)-1, 3-dioxolane-4, 5-diacetates with 1, 8-diamino-3, 6- ...