REGIOSELECTIVE, STEREOSELECTIVE, AND ENANTIOSELECTIVE ALTERNATING COPOLYMERIZATION OF PROPENE WITH CARBON-MONOXIDE

Essentially complete regioselectivity and good catalytic activity can be achieved in the copolymerization of propene with carbon monoxide us ing palladium-containing catalytic systems modified by the basic dipho sphine ligand CH2{CH2P(C2H5)2}2. With methylbiphenyl-2,2-diyl)bis(dicy clohexylphosphine) a stereoregular poly(1-oxo-2-methyltrimethylene) wa s obtained. When the optically pure ligand was used, the produced copo lymer showed an intense band in the circular dichroism spectrum in the region around 275 nm as expected for a prevailingly isotactic structu re. In most cases the copolymers can be isolated as a poly[spiro-2,5-( 3-methyltetrahydrofuran)]. NMR analysis of the regioregular copolymers and comparison with model compounds suggest that the insertion of the propene units during the growth process takes place with primary regi oselectivity.