Asymmetric polymerization of N-substituted maleimides with chiral oxazolidine–organolithium

✍ Scribed by Tsutomu Oishi; Kenjiro Onimura; Kazumi Tanaka; Wataru Horimoto; Hiromori Tsutsumi

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 236 KB
• Volume: 37
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19990215)37:4<473::aid-pola11>3.0.co;2-5

✦ Synopsis

Asymmetric anionic homopolymerizations of achiral N-substituted maleimides (RMI) were performed with lithium 4-alkyl-2,2-dialkyloxazolidinylamide. All obtained polymers were optically active, exhibiting opposite optical rotation to that of a corresponding oxazolidinyl group at the terminal of the main chain. This suggests that opposite optical rotation to the corresponding chiral oxazolidine was induced to the polymer main chain. In the polymerization using a fluorenyllithium (FlLi)-oxazolidine complex, the obtained polymer with a fluorenyl group at the polymer end showed a negative specific rotation. This also suggests that asymmetric induction took place in the polymer main chain. The asymmetric induction was supported by the circular dichroism (CD) and GPC analysis with polarimetric detector. Optical activity of the polymer was attributed to different contents of (S,S) and (R,R) structures formed from threo-diisotactic additions, as supported by the 13 C-NMR spectra of the polymers and the model compounds.