1,6-dideoxy-D-mannitol-based 20-crown-6 ethers: synthesis and influence ofthe substituents upon complexing properties toward phenylglycinium methyl esters

Ten novel homotopic 20-crown-6-ethers have been prepared from 1,3: 4,6-di-O -benzylidene-D-mannitol. Substituents could be introduced on the alditol fr amework after the macrocyclisation in order to modify their complexing abil ities. In one case, a low but significant enantiomeric excess (32% ee) in f avour of L(S)-phenylglycine methyl ester could be ascertained when two bulk y vic-triazole substituents were associated into the vicinity of the cavity . The formation of an adjacent trans-fused ring on C-3/C-4 of the mannitol framework mediated the complexing abilities of these macrocycles toward 2-p henylglycine methyl ester perchlorates.