On the chirality of polyvinyl compounds, 19 Influence of double bond position on the asymmetric cyclocopolymerization

✍ Scribed by Günter Wulff; Stefan Gladow

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 482 KB
• Volume: 196
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1995.021961021

✦ Synopsis

Abstract

Cyclocopolymerization of two new monomers, D‐mannitol 3,4‐__O‐__carbonate 1,2:5,6‐bis‐O‐[(2‐vinylphenyl)boronate] (2) and D‐mannitol 3,4‐__O‐__carbonate 1,2:5,6‐bis‐O‐[(3‐vinylphenyl)boronate] (3), was investigated. While copolymers of monomer 2, which has the double bond in ortho position, do not show optical activity after splitting off the chiral D‐mannitol template, optically active copolymers were obtained from monomer 3 with its double bond in meta position. The residual optical activity is due to the configuration of the main chain (main chain chirality). With the aid of circular dichroic (CD) spectra and optical rotation measurements the configuration of the (3‐vinylphenyl)boronic acid diads in the copolymer chain could be determined. When methyl methacrylate (MMA) was used as comonomer, the diads possessed (R,R) configuration. The mechanism of cyclopolymerization of monomer 3, which involves a 17‐membered transition state, could be explained by approximating its conformations of lowest energy with semiempirical methods (AM1).