Asymmetric-Selective Polymerization of 2,3-Epoxypropyl Methacrylate with Grignard Reagent-(−)-Sparteine Systems in Toluene at −78°C

Urakawa, Kazuhiko; Yuki, Heimei

doi:10.1295/polymj.10.473

Polym J

1978

DOI: 10.1295/polymj.10.473

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Asymmetric-Selective Polymerization of 2,3-Epoxypropyl Methacrylate with Grignard Reagent-(−)-Sparteine Systems in Toluene at −78°C

Kazuhiko Urakawa

Heimei Yuki

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1981

1998

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Cited by 4 publications

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Asymmetric‐selective polymerization of (R,S)‐α‐methylbenzyl acrylate initiated with Grignard reagent/(‐‐)‐sparteine and its modified systems

Gamaike

Yuki

1981

Makromol. Chem.

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Asymmetric-selective (or stereoelective) polymerization of racemic a-methylbenzyl acrylate (2a) was studied with Grignard reagent/( -)-sparteine and its modified catalyst system in toluene. All catalyst systems polymerized preferentially the @)-monomer over the (S)-monomer. The Grignard reagent/( -)-sparteine system showed very low activity and gave the polymer only in a few per cent yield at -78 "C. The addition of secondary amines such as piperidine and diethylamine to the catalyst system improved not only the activity but also the selectivity. The optical purity of the polymer initially formed with the cyclohexylmagnesium bromide/ (-)-sparteine/diethylamine system at -78 "C was 84%, and at about 80% polymer yield almost optically pure monomer was recovered. Asymmetric selectivity decreased with an increase of temperature. The dyad tacticity of the polymer was determined by 'H NMR spectroscopy. There was no clear correlation between the selectivity and tacticity. The role of the amines in the catalyst systems was investigated by 'H NMR spectroscopy.

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Asymmetric‐selective polymerization of (R,S)‐α‐methylbenzyl acrylate initiated with Grignard reagent/(‐‐)‐sparteine and its modified systems

Gamaike

Yuki

1981

Makromol. Chem.

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Asymmetric selective polymerization of racemic methacrylates with the cyclohexylmagnesium bromide‐(−)‐sparteine system

Okamoto

Urakawa

Yuki

1981

J. Polym. Sci. Polym. Chem. Ed.

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Asymmetric selective (or stereoelective) polymerization of various racemic methacrylates with cyclohexylmagnesium bromide (c‐HexMgBr)‐(‐)sparteine (1/1.2) catalyst was studied in toluene at −78°C. The methacrylates of α‐ethylbenzyl (EBMA), α‐isopropylbenzyl (i‐PBMA), α‐tert‐butylbenzyl (t‐BBMA), sec‐butyl (s‐BuMA), 1‐methylallyl (1‐MAMA), 2,3‐epoxypropyl (2,3‐EPMA), 2‐phenylpropyl (2‐PPMA), and menthyl (MentMA) alcohols were used as racemic monomers. In the polymerization of EBMA and i‐PBMA (S) enantiomers were consumed preferentially and the optical purity of initially polymerized i‐PBMA was as high as 97%. Optically pure (R) monomers were recovered at about 60% conversion for i‐PBMA and 80% for EBMA. In t‐BBMA, however, the (R) monomer was consumed preferentially over the (S) isomer. In the polymerization of s‐BuMA and 1‐MAMA (S) monomers were consumed in excess and the optical purity of the polymers formed in the early stage was about 30%. In 2,3‐EPMA and 2‐PPMA, which have asymmetric centers at the β position from the ester oxygen, (R) antipodes were more reactive. MentMA did not polymerize at −78°C. Enantiomer selectivity ratios rS and rR were determined in the polymerization of EBMA, i‐PBMA, and 1‐MAMA. All polymers except poly(t‐BBMA) were highly isotactic, but the tacticity of poly(t‐BBMA) could not be estimated. Circular dichroism spectra of optically active polymers of α‐substituted benzyl esters were measured.

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Chemical modification of glycidyl methacrylate polymers with 4-hydroxy-4′-methoxybiphenyl groups

Navarro-Rodríguez

Rodríguez-González

Romero‐García

et al. 1998

European Polymer Journal

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Asymmetric-Selective Polymerization of 2,3-Epoxypropyl Methacrylate with Grignard Reagent-(−)-Sparteine Systems in Toluene at −78°C

Cited by 4 publications

References 6 publications

Asymmetric‐selective polymerization of (R,S)‐α‐methylbenzyl acrylate initiated with Grignard reagent/(‐‐)‐sparteine and its modified systems

Asymmetric‐selective polymerization of (R,S)‐α‐methylbenzyl acrylate initiated with Grignard reagent/(‐‐)‐sparteine and its modified systems

Asymmetric selective polymerization of racemic methacrylates with the cyclohexylmagnesium bromide‐(−)‐sparteine system

Chemical modification of glycidyl methacrylate polymers with 4-hydroxy-4′-methoxybiphenyl groups

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