Some peculiarities of the asymmetric synthesis of macromolecules by ionic polymerization

Алиев, А. Д.; Krentsel, B. A.; Mamediarov, G.M.; Solomatina, I. P.; Tiurina, E.P.

doi:10.1016/0014-3057(71)90073-5

Cited by 14 publications

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References 18 publications

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“…La polymtrisation de 1 f avec le systtme ZnEt, /(S)-DHBN est ntgligeable A basse temptrature mais devient rapide i 4 25 Pour les composts monosubstituts, elle croit globalement avec la condensation en carbone du groupement alkyle portt par le cycle. Elle devient trts importante avec les composts disubstituts: ainsi pratiquement 50% de l e est converti en oltfine au cours de la polymtrisation.…”

Section: Polymerbation Du Methoxymethylthiiranne (1 F )unclassified

Polymérisation de thiirannes différemment substitués à l'aide du système chiral ZnEt₂/(S)‐dihydroxy‐2,2′ binaphtyl‐1,1′, 1. Stéréoélectivité de la polymérisation

Sépulchre¹

1987

Makromol. Chem.

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Differently substituted thiiranes were polymerized using an atropoisomeric chiral initiator: ZnEt, /(S)-2,2'-dihydroxy-l,1 '-binaphthyl (DHBN) (mole ratio l/l). It was observed that high stereoelectivities are obtained with monomers bearing small alkyl substituents and that the resolution efficiency of the initiator decreases as the bulkiness of the substituent increases. From the comparison of the results obtained with another initiator system, ZnEt, /(R)-3,3dimethyl-l,2-butanedioI (DMBD) (mole ratio 1 A), the use of ZnEt, /(S)-DHBN could be shown to be more suitable for the polymerization of thiiranes with linear alkyl substituents. Contrary to the case of polymerizations initiated by the system ZnEt, /(R)-DMBD, the polymerization reaction of thiiranes with ZnEt, /(S)-DHBN was usually accompanied by the production of the corresponding olefins in various amounts. 20) fait que la polymtrisation du methylthiiranne (la) avec le systkme ZnEt, /(S)-DHBN est assez proche du cas d'une polymtrisation stkrtotlective idtale dans laquelle l'amorceur choisit exclusivement l'un des tnantiomkres. Ce rtsultat remarquable nous a incitt B entreprendre l'ttude de la polymtrisation d'autres thiirannes avec le m&me systkme d'amorqage. Rtcemment, Suda et al.3) ont utilist avec succks pour la polymtrisation sttrtotlective de l'a-mtthylbenzyl mtthacrylate ractmique, un amorceur dont la composante chirale ttait constitute par un autre type de compost atropoisomere: le diamino-2,2 dimtthyl-6,6' biphtnyl-1 ,l '. 0025-1 16)3/87/$03.00 1584 M. Sepulchre A B Dans le prksent article, nous dtcrivons les polymkrisations de plusieurs Chiirannes diffkremment substituks tels que l'kthylthiiranne (1 b), l'isopropylthiirannk (lc), le butylthiiranne (ld), l'kthyl-2 mkthyl-2 thiiranne (le), le mkthoxymkthylthiiranne (If), le sec-butylthiiranne (lg) et enfin le tert-butylthiiranne (lh) avec le systeme ZnEt, /(S)-DHBN en nous attachant surtout A l'aspect stkrkoklectif du processus.

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Section: Polymerbation Du Methoxymethylthiiranne (1 F )unclassified

Polymérisation de thiirannes différemment substitués à l'aide du système chiral ZnEt₂/(S)‐dihydroxy‐2,2′ binaphtyl‐1,1′, 1. Stéréoélectivité de la polymérisation

Sépulchre¹

1987

Makromol. Chem.

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Living enantiosymmetric and enantioasymmetric polymerization of methylthiirane in homogeneous phase

Dumas

Sigwalt

1991

Chirality

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The polymerization of racemic methylthiirane in homogeneous phase, initiated by bis(isopropy1-S-cysteinato) cadmium is a living process. The resulting polymers are isotactic and optically active at partial conversion. The optical purity of the residual monomer may reach 27% at half conversion. The propagation occurs mainly on one valency of Cd, however oligomers grow slowly on the second valency. The stereoregularity of the polymer chain appears only when the length of the oligomer becomes high enough, making possible a bicoordination of the Cd counterions. The stereoregularity of the polymer is characterized by the molar fraction G of isotactic diads which varies from 0.5 for atactic chains-formed at the beginning-to about one for isotactic segments formed for longer chains. The stereospecificity also depends on temperature of propagation and on initiator concentration. The kinetics observed (zero order in monomer and one-half in Cd) are explained by monomer coordination before insertion and dimeric association of the thiolate end groups. The enantioasymmetric process observed results from an unbalance in the number of the two different types of active sites and possibly from a difference in their reactivities. Enantioasymmetry has been found to decrease significantly when the dielectric constant E of the medium increases.

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Stereospecific and anionic ring‐opening polymerization

Spassky

1991

Makromolekulare Chemie. Macromolecular Symposia

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15 Nicolas SPASSKY Laboratoire de Chimie MacromolCculaire, URA 24 Universitt Pierre et Marie Curie, 4, Place Jussieu -75252 Paris C a e x 05 -France Abstract :The polymerization features of the polymerization of heterocyclic monomers using anionic or coordinated anionic type initiators are examined. The chemical and configurational structure of initiating species depends on the regiospecificity of the ring-opening reaction. Propagating rate constants, solvation and macrocyclisation phenomena are discussed. The structure and the chemical composition of stereospecific initiators are described. Different types of mechanisms (enantiomorphic sites and endchain) are illustrated. The dependence of selectivity on different parameters is discussed. Various aspects of chiral catalysis leading to stereoelective and enantiogenic processes are presented. Some examples of recent trends in anionic and stereospecific ring-opening polymerization are given. 0 1991 Hiithig & Wepf Verlag, Basel CCC 0258-0322/91/$02.00

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Some peculiarities of the asymmetric synthesis of macromolecules by ionic polymerization

Cited by 14 publications

References 18 publications

Polymérisation de thiirannes différemment substitués à l'aide du système chiral ZnEt₂/(S)‐dihydroxy‐2,2′ binaphtyl‐1,1′, 1. Stéréoélectivité de la polymérisation

Polymérisation de thiirannes différemment substitués à l'aide du système chiral ZnEt₂/(S)‐dihydroxy‐2,2′ binaphtyl‐1,1′, 1. Stéréoélectivité de la polymérisation

Living enantiosymmetric and enantioasymmetric polymerization of methylthiirane in homogeneous phase

Stereospecific and anionic ring‐opening polymerization

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Some peculiarities of the asymmetric synthesis of macromolecules by ionic polymerization

Cited by 14 publications

References 18 publications

Polymérisation de thiirannes différemment substitués à l'aide du système chiral ZnEt2/(S)‐dihydroxy‐2,2′ binaphtyl‐1,1′, 1. Stéréoélectivité de la polymérisation

Polymérisation de thiirannes différemment substitués à l'aide du système chiral ZnEt2/(S)‐dihydroxy‐2,2′ binaphtyl‐1,1′, 1. Stéréoélectivité de la polymérisation

Living enantiosymmetric and enantioasymmetric polymerization of methylthiirane in homogeneous phase

Stereospecific and anionic ring‐opening polymerization

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Polymérisation de thiirannes différemment substitués à l'aide du système chiral ZnEt₂/(S)‐dihydroxy‐2,2′ binaphtyl‐1,1′, 1. Stéréoélectivité de la polymérisation

Polymérisation de thiirannes différemment substitués à l'aide du système chiral ZnEt₂/(S)‐dihydroxy‐2,2′ binaphtyl‐1,1′, 1. Stéréoélectivité de la polymérisation