On the chirality of polyvinyl compounds, part 17. Investigations on main-chain chiral copolymers with alternating structure

✍ Scribed by Günter Wulff; Stephan Krieger

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 479 KB
• Volume: 195
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1994.021951114

✦ Synopsis

Abstract

3,4‐O‐Cyclohexylidene‐D‐mannitol 1,2:5,6‐bis‐O‐[(4‐vinylphenyl)boronate] (M 1) was copolymerized with methyl methacrylate (MMA) in presence of AlEt~1,5~ or SnCl~4~. The expected alternating bis(4‐vinylphenylboronic acid)‐MMA triad structures were only formed to a lesser extent. Instead, predominantly alternating 4‐vinylphenylboronic acid‐MMA structures were obtained. Since no crosslinking was observed, a cyclocopolymerization must have occurred. In this case an MMA unit is inserted between the two styrene residues of M 1, thus forming a 21‐membered ring system. Copolymerization forming alternating 4‐vinylphenylboronic acid‐MMA diads is apparently even faster than the direct copolymerization forming distyryl diads. After removal of the template (3,4‐O‐cyclohexylidene‐D‐mannitol), these copolymers still show pronounced optical activity and circular dichroism with a negative Cotton effect at 233 nm. After deboronation of the copolymers, optically active, predominantly alternating styrene‐MMA copolymers are obtained.