Stereospecific and asymmetric polymerization of 1‐phenyldibenzosuberyl methacrylate with radical and anionic initiators

Stereospecific and asymmetric (helix‐sense‐selective) polymerization of 1‐phenyldibenzosuberyl methacrylate (PDBSMA) was performed with radical and anionic initiators. A highly isotactic polymer having triad isotacticity greater than 97% was obtained by radical polymerization with ( i ‐PrOCOO) 2 at 40°C. The radical polymerization of PDBSMA in (+)‐ and (‐)‐menthol gave (‐)‐and (+)‐polymers, respectively, whose optical activity is ascribed to the prevailing one‐handed helical conformation of a polymer chain. The radical copolymerization of PDBSMA with a small amount of an optically active monomer, (+)‐phenyl‐2‐pyridyl‐ o ‐tolylmethyl methacrylate, afforded an optically active copolymer with the prevailing one‐handed helical structure of PDBSMA sequences. Asymmetric anionic polymerization of PDBSMA was carried out with the complex of N, N ′‐diphenylethylenediamine monolithium amide and a chiral ligand, (+)‐1‐(2‐pyrrolidinylmethyl)pyrrolidine in toluene at −78°C. The obtained polymer was highly isotactic and optically active due to nearly 100% one‐handed helical structure.