Synthesis and chiral recognition of helical polymers

Asymmetric syntheses of optically active polymethacrylate, polyacrylate, polyacrylamide, and polyisocyanate with helical conformation and their chiral recognition abilities are described. 1-Phenyldibenzosuberyl methacrylate (PDBSMA) gave a purely one-handed-helical, optically active polymer([alpha](365) + 1670 similar to + 1780 degrees) with almost perfectly isotactic structure by anionic polymerization using optically active initiators. Radical polymerizations of PDBSMA using chiral initiators, chain transfer agents, and additives also afforded optically active polymers with a prevailing one-handed helicity. Triphenylmethyl acrylate yielded an optically active, helical polymer ([alpha](365)+ 102 degrees) having a dyad isotacticity of 70% using an optically active 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 -Chlorophenyl)-N-phenylacrylamide gave an optically active, helical polymer ([alpha](365) - 343 degrees) in the asymmetric anionic polymerization; the polymer had a dyad tacticity of 77%. Optically active polyisocyanates with a predominantly one-handed helical conformation were prepared in homo and co-polymerization of optically active phenyl isocyanate derivative. These polyisocyanates showed the ability to discriminate enantiomers in solution.