Preparation,characterization, and porperties of optically active poly(α-methyl-α-ethyl-β-propiolactones)

S(?) and R(+) enantiomers of α-methyl-α-ethyl-β-propiolactone (MEEPL) were prepared in an eight-step synthesis with respective optical purities of 99 and 97% determined by ¹H-NMR (250 MHz) spectroscopy. Polymers (PMEPL) of different enatiomeric compositions were prepared with an anionic-type initiator. Substantial differences in physical properties were observed between the racemic and optically pure polymers; for example, the melting point of the latter is 42°C higher than that of the former. Chiroptical properties of PMEPLs are reported. The ¹³C-NMR (100.62 MHz) spectra of the polymers indicated that the distribution of configurational units in the macromolecular chain is random.