Asymmetric induction arising from the chiral twist of 2,2′‐binaphthyl template in the cyclopolymerization of divinyl ethers
1992; Wiley; Volume: 193; Issue: 8 Linguagem: Inglês
10.1002/macp.1992.021930802
ISSN0025-116X
AutoresKazuaki Yokota, Toyoji Kakuchi, Yamamoto Toshiya, Toshiyuki Hasegawa, Osamu Haba,
Tópico(s)Synthesis and Properties of Aromatic Compounds
ResumoAbstract Cationic cyclopolymerization of divinyl ethers, which were derived from ( R )‐ or ( S )‐1, 1′‐bi‐2‐naphthol with methyl, phenyl, and bromo groups in the 3,3′‐positions, yielded polymers with changing optical rotation according to the reaction conditions. Model compounds, therefore, corresponding to the three stereoisomeric forms of the constitutional units, i. e., two racemo ( R , R ‐and S , S ‐) forms and one meso form, were synthesized to confirm the origin of changing optical rotation in the polymers. 1 H NMR analysis showed that the polymers change their optical rotation due to the configuration, which has a tendency to be preferentially a racemo‐diisotactic structure at higher monomer concentrations and in less polar solvents. The chiral twist of the ( R )‐or ( S )‐binaphthyl template induces the main chain to form an asymmetric R , R ‐ or S , S ‐racemo sequence, respectively, in the cyclopolymerization.
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