Preparation of stereoregular isotactic poly(mandelic acid) through organocatalytic ring-opening polymerization of a cyclic O-carboxyanhydride.

Poly(mandelic acid) (PMA) is an aryl analogue of poly(lactic acid) (PLA) and a biodegradable analogue of polystyrene. The preparation of stereoregular PMA was realized using a pyridine/mandelic acid adduct (Py⋅MA) as an organocatalyst for the ring-opening polymerization (ROP) of the cyclic O-carboxyanhydride (manOCA). Polymers with a narrow polydispersity index and excellent molecular-weight control were prepared at ambient temperature. These highly isotactic chiral polymers exhibit an enhancement of the glass-transition temperature (T(g)) of 15 °C compared to the racemic polymer, suggesting potential future application as high-performance commodity and biomedical materials.

Group 4 initiators for the stereoselective ROP of rac-ß-butyrolactone and its copolymerization with rac-lactide.

In this paper we demonstrate the utility of Group 4 metals for the well-controlled and stereoselective (syndiotactic) ring opening polymerization (ROP) of rac-ß-butyrolactone (BBL) and their ability to form copolymers.