Polymeric chiral crown ethers, 7. Synthesis of polymers incorporating methyl glycosides of α-D-altrose, α-D-galactose, α-D-glucose and α-D-mannose residues via copolymerization of divinyl ethers

Polymers with chiral asymmetric crown ether units ( 5, 6, 7 and 8 ) were synthesized via cationic cyclopolymerization of methyl 2,3-bis{O-[2-(2-vinyloxyethoxy)ethyl]}-4,6-O-benzylidene α-D -altro-, α-D -galacto-, α-D -gluco- and α-D -manhopyranosides ( 1, 2, 3 and 4 ), respectively. The enantioselective transport of the methyl ester of phenylglycine (PhGlyOCH₃) and phenylalanine (PhAlaOCH₃) was examined through a bulk chloroform solution of chiral polymers from one aqueous solution to another. The transport rate of PhAlaOCH₃ was larger than that of PhGlyOCH₃ for every host polymer. For polymer 7 , the optical purity of PhAlaOCH₃ transported from one to the other phase was 12,6%, and the ratio of rate constants for the faster moving enantiomer A and the slower moving enantiomer B (k_A^*/k_B^*) was 1,48. The faster moving enantiomer was the L -isomer except for the systems polymer 7 ? PhAlaOCH₃ and polymer 8 ? PhAlaOCH₃. This enantioselectivity is caused by the diastereotopic faces of the crown ether units in the host polymers.