SYNTHESIS AND CHIRAL RECOGNITION OF HELICAL POLYMERS

Asymmetric syntheses of optically active polymethacrylate, polyacrylat e, polyacrylamide, and polyisocyanate with helical conformation and th eir chiral recognition abilities are described. 1-Phenyldibenzosuberyl methacrylate (PDBSMA) gave a purely one-handed-helical, optically act ive polymer([alpha](365) + 1670 similar to + 1780 degrees) with almost perfectly isotactic structure by anionic polymerization using optical ly active initiators. Radical polymerizations of PDBSMA using chiral i nitiators, chain transfer agents, and additives also afforded opticall y active polymers with a prevailing one-handed helicity. Triphenylmeth yl acrylate yielded an optically active, helical polymer ([alpha](365) + 102 degrees) having a dyad isotacticity of 70% using an optically ac tive anionic initiator. Although the polyacrylate demonstrated chiral recognition ability as a chiral stationary phase for HPLC, the ability was low mainly because of the low degree of one-handedness. N-(3 -Chl orophenyl)-N-phenylacrylamide gave an optically active, helical polyme r ([alpha](365) - 343 degrees) in the asymmetric anionic polymerizatio n; the polymer had a dyad tacticity of 77%. Optically active polyisocy anates with a predominantly one-handed helical conformation were prepa red in homo and co-polymerization of optically active phenyl isocyanat e derivative. These polyisocyanates showed the ability to discriminate enantiomers in solution.