Isotactic degradable polyesters derived from O-carboxyanhydrides of L-lactic and L-malic acid using a single organocatalyst/initiator system

The preparation of stereoregular isotactic P(L-BnMA) and PLLA by ring-opening polymerization (ROP) of 5-(S)-[(benzyloxycarbonyl)methyl]-1,3-dioxolane-2,4-dione (L-malOCA) and (S)-5-methyl-1,3-dioxolane-2,4-dione (L-lacOCA) is reported. The polymerization process was shown to be well controlled using two easily accessible single organocatalyst/initiator systems, pyridine/L-benzyl(Bn)malate and pyridine/lactic acid (Py.LA) ion pair adducts respectively. The obtained biodegradable polymers displayed narrow dispersity (D-M) and excellent molar mass control. All ROP reactions were conducted at ambient temperature. The stereoregularity and thermal properties of the materials were thoroughly studied, demonstrating the retention of high levels of isotactic enrichment.