Copolymerization of 7-Methylenebicyclo[4.1.0]heptane with Carbon Monoxide Initiated by Optically Active Palladium Complexes
✍ Scribed by Daisuke Takeuchi; Ayami Yasuda; Takeshi Okada; Junpei Kuwabara; Kohtaro Osakada; Katsuhiko Tomooka
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- German
- Weight
- 170 KB
- Volume
- 89
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
Seven Pd‐complexes with optically active bis[dihydroxazole]‐type ligands promote asymmetric alternating copolymerization of 7‐methylenebicyclo[4.1.0]heptane with CO, which produces an optically active polyketone, [C(CH~2~)COC~6~H~10~]~n~. The reaction under increased CO pressure (> 5 atm) affords a polymer that contains monomer units with the cis‐cyclohexane‐1,2‐diyl group almost exclusively. The polyketone exhibits positive or negative optical rotation depending on the Pd‐complex. The highest and lowest [α]$\rm{_{{D}}^{25} }$ of the polymer obtained are + 68.9 and − 76.1, respectively. Addition of dibutylcuprate to a solution of the polymer in the presence of Me~3~SiCl transforms the enone groups of the polymer to silyl enol ether groups, which are ozonized to (silyloxy)oxirane moieties.