Abstract: Enantioselective alternating copolymerization of carbon monoxide with ω undecylenic acid was carried out using cationic palladium catalyst modified by 1,4-3,6-dianhydro-2,5-dideoxy-2,5-bis(diphenylphosphino)-L-iditol (DDPPI). The chiral diphosphine was proved to be effective in the enantioselective copolymerization. The pure poly(1,4-ketone) was obtained by dissolving the copolymer containing spiroket al and 1,4-ketone units in₁,1,1,3,3,3-hexafluoro-2-propanol and reprecipitating with methanol. Optical rotation, elemental analysis, spectra of ¹H NMR, ¹³C NMRand IRshowed that our copolymer was an optically active, isotatic, alternating poly(1,4-ketone) structure. The copolymerization was carried out at 45 ℃ for 20 h. Molecular weight: M_n=1.1× 10⁴ versus polystyrene,M_w/M_n=1.84. Molar optical rotation: [α]₅₈₉²⁰ =+43°(CH₃COOC₂H₅, 5.0 mg/mL). The productivity of the copolymer of ω-undecylenic acid with carbon monoxide was 40.6 g copolymer/(g Pd·h).

Key words: Cationic palladium catalyst, Chiral ligand, Enantioselective alternating copolymerization, Isotactic copolymer, Optical activity