Polymeric chiral crown ethers, 4. Substituent effects of methyl and phenyl groups in the 3,3′‐positions on chiral recognition of poly(crown ether)s synthesized by cyclopolymerization of divinyl ethers derived from 1,1′‐bi‐2‐naphthol

Chiral poly(crown ether)s were synthesized by cationic cyclopolymerization of (S)‐2,2′‐bis(2‐vinyloxyethoxy)‐3,3′‐dimethyl‐1,1′‐binaphthyl [(S)‐1b] and (R)‐2,2′‐bis[2‐(2‐vinyloxyethoxy)‐ethoxy]‐3,3′‐dimethyl (or 3,3′‐diphenyl)‐1,1′‐binaphthyl [(R)‐3b or (R)‐3c]. The substituents in the 3,3′‐positions of binaphthyl moiety disturb the intramolecular cyclization in the polymerization of monomer (S)‐1b, but have no influence on the cyclopolymerization tendency of monomers (R)‐3b and (R)‐3c. The polymers from (R)‐3b and (R)‐3c [(R)‐4b and (R)‐4c] have a higher ability of chiral recognition towards a‐amino acids, such as phenylglycine, phenylalanine, valine, and methionine, than the polymer from (R)‐3a [(R)‐4a], which has no substituent in 3,3′‐positions. The methyl and the phenyl substituents in the 3,3′‐positions undoubtedly act as additional barrier causing an increase in the ability of chiral recognition, though the effect is less than expected from the result of model crown ethers.