Polymeric chiral crown ethers, 3 Synthesis of polymers incorporating D-mannitol moieties via cyclopolymerization,and chiral recognition towards α-amino acids

A novel approach to the production of chiral, polymeric crown ethers incorporating D-mannitol moieties was developed. Three optically active divinyl ethers (3, 6 and 9) , derived from 1,3 : 4,6-di-O-benzylidene-, 1,2 : 5,6-diisopropylidene- and 1,4 : 3,6-dianhydro-D-mannitol (2, 5 and 8) were polymerized with cationic catalysts. The cyclopolymerization led to the chiral polymeric crown ethers 4, 7 and 10 consisting of only cyclic constitutional units. Both monomer 9 and polymer 10 , containing 1,4 : 3,6-dianhydro-D-mannitol moieties are amphiphilic compounds. Polymer 4 with 1,3 : 4,6-di-O-benzylidene-D-mannitol moieties was found to exhibit chiral recognition in favour of the (S)-isomer of racemic ester salts of phenylglycine, phenylalanine, valine and methionine. The ability of chiral recognition, which was estimated as enantiomer distribution constants (EDC), is comparable to that of polymeric crown ethers with (R)-2,2′-binaphthyl moieties.