Regioselectivity of the insertion of propene with achiral Pd(II) catalyststo highly isotactic poly[1-oxo-2-methylpropane-1,3-diyl]. Is the syndiotactic structure accessible?

Achiral cationic palladium catalysts, modified with 1,2-bis(diarylphosphino methyl)benzene ligands with different electronic properties, can efficientl y produce poly(propene-alt-CO) with essentially complete regioregularity an d high isotacticity, depending on the aryl substituent; the stereochemistry of the copolymers obtained is barely, if at all, influenced by the regioch emistry of the olefin insertion.