Helix-sense-selective copolymerization of phenyl[bis(2-pyridyl)]methyl methacrylate, diphenyl(2-pyridyl)methyl methacrylate and triphenylmethyl methacrylate with chiral anionic initiators

✍ Scribed by Changyu Ren; Chuanfu Chen; Fu Xi

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 129 KB
• Volume: 36
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19980915)36:12<2127::aid-pola19>3.0.co;2-8

✦ Synopsis

Optically active poly[triphenylmethyl methacrylate-co-phenyl[bis(2pyridyl)]methyl methacrylate] (poly[TrMA-co-PB2PyMA], poly[diphenyl(2-pyridyl)methyl methacrylate-co-phenyl[bis(2-pyridyl)]methyl methacrylate] (poly[D2PyMAco-PB2PyMA]), and poly[triphenylmethyl methacrylate-co-diphenyl(2-pyridyl)methyl methacrylate] (poly[TrMA-co-D2PyMA]) were prepared by helix-sense-selective copolymerization with complexes of organolithium with ( 0)-sparteine [( 0)Sp], (S, S)-(/)-and (R, R)-(0)-2,3-dimethoxy-1,4-bis(dimethylamino)butane [( /)-and (0)DDB], and (S)-(/)-2-(1-pyrrolidinylmethyl)pyridine [( /)PMP] as anionic initiators in toluene at low temperature. The copolymers obtained with ( 0)Sp and (/)DDB or ( 0)DDB complexes of organolithium showed low optical activity, but to [( /)PMP] complex with N,N-diphenyleneamine monolithium amide [( /)PMP-DPEDA-Li)] was effective in synthesizing copolymers of high optical rotation ([ a] 25

D about /320 to /370Њ) which were comparable to those of corresponding homopolymers with onehanded helical structure. The optical rotations of poly [TrMA-co-PB2PyMA] and poly [TrMA-co-D2PyMA] were much more stable than that of poly(D2PyMA) or poly(PB2PyMA) in a solution of CHCl 3 -2,2,2-trifluoroethanol (10 : 1, v/v) at 25ЊC, but optical rotation of poly[D2PyMA-co-PB2PyMA] slowly decreased with time in the same conditions.