Stereospecific polymerization of alpha-(menthoxymethyl)acrylate

Novel alpha-(alkoxymethyl)acrylates bearing a chiral substituent, racemic a nd optically active benzyl alpha-(menthoxymethyl)acrylates ((+/-)- and (-)- BMnMA), were synthesized and polymerized by radical and anionic methods. Th e effects of the chiral substituent on the stereoregularity and chiroptical property of the obtained polymers were investigated. C-13 NMR spectra of t he polymers obtained by anionic polymerization of the racemic monomer showe d sharper peaks than that of the radically obtained polymers, indicating th at the former polymers possessed higher stereoregularity than the radically obtained polymers. The polymers prepared from optically pure (-)-monomer w ith anionic initiators had low solubility in common organic solvents. Howev er, the THF-soluble parts were highly isotactic, and exhibited lower specif ic rotation ([alpha](365)(25)= -92 degrees) than those of the monomer ([alp ha](365)(25) = -226 degrees) and the radically obtained polymer ([alpha](36 5)(25) = -201 degrees). The circular dichroism (CD) spectra of the copolyme rs prepared from a (+)- and (-)-monomer mixture with various optical purity suggested that the highly isotactic (-)-polymer may possess a chiral helic al conformation.