Asymmetric-Selective Polymerization of (RS)-α-Methylbenzyl Methacrylate with the Cyclohexylmagnesium Chloride-(---)- Sparteine System in Toluene at -78 °C

Ohta, Koji; Yuki, Heimei

doi:10.1021/ma60064a021

Cited by 42 publications

(18 citation statements)

References 3 publications

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“…3 The polymerization in an NMR sample tube (5-mm diameter) was carried out under dry nitrogen according to the method of Okamoto. 26 As the polymerization medium, we used toluene-d 8 containing a small amount of toluene as an intensity standard. The monomer (0.05 ml) and solvent (0.3 ml) were mixed in the degassed tube and cooled at -78°C.…”

Section: Polymerizationmentioning

confidence: 99%

Highly Asymmetric-selective and Stereoselective Polymerization of (RS)-α-Methylbenzyl Methacrylate with Cyclohexyl-magnesium Bromide-Axially Dissymmetric 2,2′-Diamino-6,6′-dimethylbiphenyl System

Kanoh

Goka

Murose

et al. 1987

Polym J

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ABSTRACT:Enantiomer-selective polymerization of (RS)-IX-methylbenzyl methacrylate [(RS)-MBMA] was investigated in toluene at -30oc. Reaction products between cyclohexylmagnesium bromide (cHexMgBr) and axially dissymmetric 2,2 '-diamino-6,6' -dimethylbiphenyl (AMB) in the mole ratio of 1.5: I were used as a chiral initiating system. The polymer produced a biphenyl group from the catalyst fragment. The polymerization proceeded in an anionic coordination mechanism and the racemic monomer was kinetically resolved during the course of the reaction. The enantiomer selectivity ratio when using (R)-AMB was estimated to be r

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Section: Polymerizationmentioning

confidence: 99%

Highly Asymmetric-selective and Stereoselective Polymerization of (RS)-α-Methylbenzyl Methacrylate with Cyclohexyl-magnesium Bromide-Axially Dissymmetric 2,2′-Diamino-6,6′-dimethylbiphenyl System

Kanoh

Goka

Murose

et al. 1987

Polym J

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“…22 The absence of coordination mechanism in free-radical polymerization is considered to be responsible for the rather low selectivity.…”

mentioning

confidence: 99%

Helix-Sense-Selective and Enantiomer-Selective Polymerization of a Chiral Methacrylate by Anionic and Free-Radical Mechanisms

Kinjo

Hidaka

1999

Polym J

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ABSTRACT:( ± )-1 O.ll-0-lsopropylidene-lrans-1 0.11-dihydroxy-5-phcnyl-1 O.ll-dihydro-5H-dibcnzo[a.d]cyclohcptcnc-5-ylmcthacrylate (IDPDMA) was synthesized and resolved into an optically pure form by chiral HPLC. Anionic polymerization of lDPDMA was carried out using the complexes of N.N'-diphcnylcthylcnediamine monolithium amide (DPEDA-Li) with 1 + )-1-(2-pyrrolidinylmethyl)pyrrolidine. ( + )-2.3-dimethoxy-1.4-bis(dimcthylamino )butane. and (-)-sparteine in toluene at 7R Cor using DPEDA-Li in tetrahydrofuran at -78 C. The polymers obtained from the racemic monomer using the chiral initi

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“…The ee of the polymer is highest at the beginning and then decreases, and that of the monomer gradually increases and reaches nearly 100% at about 60% conversion. 16 Therefore, PEMA enantiomers are kinetically resolved. An ESP is a kind of copolymerization of R-and S-monomers, and so the reaction is expressed by the enantiomer selectivity ratios, r S and r R , which correspond to the monomer reactivity ratios, r 1 and r 2 , in the copolymerization of M 1 and M 2 monomers, respectively.…”

Section: Enantiomer-selective Polymerization (Esp) Of Racemic Methacrmentioning

confidence: 99%

(−)‐Sparteine: The compound that most significantly influenced my research

Okamoto

2004

J. Polym. Sci. A Polym. Chem.

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A chiral diamine alkaloid, (−)‐sparteine (Sp), has been found to be very effective as a ligand for Grignard reagents when used for the enantiomer‐selective polymerization of racemic RS‐1‐phenylethyl methacrylate. The enantiomeric excess of the initially polymerized monomer is 93%, and at about a 60% conversion, nearly optically pure R‐monomer is recovered. This enantiomer selectivity is today the highest in polymer chemistry. Triphenylmethyl methacrylate (TrMA) is a unique monomer that gives a highly isotactic polymer even during radical polymerization. When TrMA is polymerized with the Sp complex with n‐butyllithium in toluene at −78 °C, an optically active, isotactic polymer [poly(triphenylmethyl methacrylate) (PTrMA)] with a one‐handed helical conformation is obtained. The helical structure is maintained even at room temperature in solution. Analogous helical polymethacrylates that show various conformational changes have also been found. One‐handed helical PTrMA exhibits high chiral recognition to a variety of racemates as a chiral stationary phase (CSP) for high‐performance liquid chromatography. This finding has led to the development of very powerful CSPs based on polysaccharides, such as cellulose and amylose. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4480–4491, 2004

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Asymmetric-Selective Polymerization of (RS)-α-Methylbenzyl Methacrylate with the Cyclohexylmagnesium Chloride-(---)- Sparteine System in Toluene at -78 °C

Cited by 42 publications

References 3 publications

Highly Asymmetric-selective and Stereoselective Polymerization of (RS)-α-Methylbenzyl Methacrylate with Cyclohexyl-magnesium Bromide-Axially Dissymmetric 2,2′-Diamino-6,6′-dimethylbiphenyl System

Highly Asymmetric-selective and Stereoselective Polymerization of (RS)-α-Methylbenzyl Methacrylate with Cyclohexyl-magnesium Bromide-Axially Dissymmetric 2,2′-Diamino-6,6′-dimethylbiphenyl System

Helix-Sense-Selective and Enantiomer-Selective Polymerization of a Chiral Methacrylate by Anionic and Free-Radical Mechanisms

(−)‐Sparteine: The compound that most significantly influenced my research

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