Preparation and investigation of optically active polyesters from α-ethyl-α-phenyl-β-propiolactone, 1

α-Ethyl-α-phenyl-β-propiolactone ( 7 ) of an optical purity up to 95% was prepared; the resolution of the two optical antipodes was carried out with the optical active precursor ethyl 2-aminomethyl-2-phenylbutyrate ( 5 ), and the optical purity was determined by ¹H NMR analysis using europium salt shift reagents. The solution and thermal properties of the corresponding polyesters 8 , as obtained by anionic ring opening polymerization, were investigated. It was found that the inherent viscosity increased with the optical purity of the lactone. Distinct differences in the melting behaviour were found between the racemic and the optically active polymers; the ideal melting temperature T_M⁰ for the pure enantiomeric polymer was estimated to about 535 K.