Anionic polymerization of optically active oxiranes

The anionic bulk polymerization of optically active (2R, 3S)-3,4-epoxy-1,2-O-isopropylidenebutane-1,2-diol ( 1 ) and its (2 S, 3 S) diastereomer 2 was studied. Molecular weights and optical activity measurements as well as carbon and proton NMR spectra are reported. The polymers show solvent dependent inversion of the sign of optical rotation. The NMR spectra are consistent with isotactic polymer chains.