Anionic polymerization methyl sorbate

Amplification. See Chirality amplification Anhydrides, ring opening, 331 Anionic polymerization methyl sorbate, 174 trityl acrylate, 181 Annelation, Robinson method, 336 Antibiotics, 8, 44, 80 Antibodies, 12... 

Natta carried out the anionic polymerization of methyl sorbate, a 1,3-diene, with an optically active initiator and obtained an optically active homopolymer with main-chain chirality. The high molecular weight crystalline polymer produced with (P)-2-methylbutyllithium had a tritactic (di-iso-rra/w-tactic) structure. This was probably the first metal-catalyzed asymmetric polymerization 134). Polymerization of other dienes was attempted by using various asymmetric methods 135). 

In 1960, Natta reported the first direct synthesis of an optically active polymer from an achiral monomer, where methyl sorbate was polymerized using (R)-2-pentyllithium [95]. Ozonolysis of the polymer (under conditions possibly allowing epimerization) produced (S)-methyl succinic acid in 5% ee, which provides evidence of asymmetric induction and absolute configuration of the polymer main chain. Since this initial report, a remarkable void in the Hterature exists concerning the synthesis of main-chain chiral polymers from achiral monomers using anionic initiators. Okamoto and Oishi have polymerized N-substituted maleimides with chiral anionic initiators (Scheme 14) [96,97]. The polymer is assumed to have predominantly a frans-diisotactic microstructuxe, which adopts a secondary helical structure. The absolute configuration of the main chain has... 

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See also in sourсe #XX -- [ ]

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