Highly heteroselective ring-opening polymerization of racemic lactide initiated by divalent ytterbium complexes bearing amino bis(phenolate) ligands

Polymerization of racemic lactide initiated by divalent ytterbium complexes supported by either dimethylamino-amino bis(phenolate) or methoxy-amino bis(phenolate) ligands proceeds rapidly at room temperature in a living fashion to give heterotactic polylactide with the racemic enchainment of monomer units P-r ranging from 0.97-0.99.