Polycyclic trans-fused crown ethers from D-mannitol

Abstract New macrocyclic ethers, all bearing a common trans -fused chiral dioxepan moiety, were easily synthesized from 1,3:4,6-di- O -benzylidene- d -mannitol in 5 or 6 steps (3 examples). The influence of the substituent at C-1/C-6 positions upon conformation is discussed.