Polymers. III. Synthesis of Optically Active Stereoregular Polyolefins<sup>1-3</sup>

Bailey, William J.; Yates, Edwin T.

doi:10.1021/jo01080a033

Cited by 53 publications

(17 citation statements)

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“…Good evidence for this was obtained by Pino (7) and Bailey (8), who showed that isotactic polymers of alpha olefins containing asymmetric side groups had optical rotations in solution up to 28 times those expected from the structures of the side groups. This increase in optical activity was proportional to isotactic content.…”

Section: Geometry Of Tactic Polymersmentioning

confidence: 88%

Stereospecific Polymerization

Ketley¹,

Werber²

1964

Science

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The great flurry of activity which followed the announcement of Ziegler and Natta's initial results has led to the discovery of an enormous number of catalyst systems which are effective in stereospecific polymerization. However, there is little more understanding now than in 1955 of how most of these systems work. Now that the initial excitement has cooled, a larger amount of thoughtful work on the mechanisms of these reactions should appear. As a basis for understanding both the heterogeneous and homogeneous systems, more mechanism studies in organometallic chemistry are urgently needed. More specifically for the heterogeneous catalysts, continued attempts should be made to find better models for the active sites, and new analytical methods should be sought to provide more information concerning the active site itself. In homogeneous systems, greater understanding of the ion pairs, the structure of which is so critical, could be obtained by the preparation and study of nonpolymeric analogues. In addition to understanding better the catalysts that we already have, we may see in the future the development of new kinds of catalysts. Some of these may be capable of producing polymers in which the units have a more complex code than in those produced by simple stereospecific catalysts. Such catalysts already exist in nature. For example, we now know that the RNA molecule functions as a multifunctional catalyst in peptide syntheses, each sequence of three bases along the backbone corresponding to a particular amino acid. The molecule consequently acts as a catalytic template which defines the order in which these amino acids polymerize into the final peptide (32). Synthetic RNA's have also been prepared containing only one base such as uracil along the chain (33). Since three uracil units correspond to phenylalanine, the polyuracil acts as a template for the formation of a peptide containing only this amino acid. There seems no reason why, ultimately, we should not be able to synthesize polymeric catalysts of this type which can act as templates for the polymerization of specific monomers other than those found in living systems. If a number of systems such as this can be found, we will be on the road to producing catalysts which can not only control the stereochemistry of a polymer chain but also the order in which a group of different monomers can enter into it.

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Section: Geometry Of Tactic Polymersmentioning

confidence: 88%

Stereospecific Polymerization

Ketley¹,

Werber²

1964

Science

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“…[10] There were two isolatable fractions: a partially crystalline xylene insoluble fraction with a specific rotation of +94.9, and a highly crystalline xylene soluble fraction with a specific rotation of ±257. The first polymer was believed to be atactic, whereas the latter was believed to be isotactic with a predominance of one enantiomer in the main chain.…”

Section: Chiral Vinyl Hydrocarbon Polymersmentioning

confidence: 98%

“…[9] This was the opposite of the findings for straight-chain branches, such as the isotactic polymerization of 1-hexene, which has a melt transition below room temperature. [10] Two explanations were given for the unexpected high crystallinity of the racemic polymer: the hydrocarbon branch did not affect the crystalline lattice, or the individual polymer was composed of only one enantiomer. [11] Much research was performed in the 1960s and 1970s to determine the reasons for the high degree of crystallinity.…”

Section: Chiral Vinyl Hydrocarbon Polymersmentioning

confidence: 99%

Chiral Polyolefins

Hopkins

Wagener²

2002

Adv. Mater.

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The synthesis and optical properties of a variety of chiral polyolefins are reviewed. The polymers are separated into four categories: hydrocarbon‐based chiral polyolefins, chiral polyolefins from achiral monomers, chiral polyolefins with aromatic side chains, and chiral polyolefins bearing branched amino acids. The polymers were synthesized using Ziegler–Natta, anionic, radical, and acyclic diene metathesis (ADMET) polymerization techniques.

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“…Chiral synthetic polymers can be classified as: addition polymers, condensation polymers and cross-linked gels. Addition polymers are including vinyl, aldehyde, isocyanide and acetylene polymers that were prepared via addition polymerization reaction such as poly(acryl amide)s, polyolephynes, polystyrene derivatives, polyazulenes, poly(vinyl ether)s, polymethacrylate, polymethacryloylamine, polychloral, polyisocyanides, polyisocyanates, polyacethylene and polyethers [39][40][41][42][43][44][45]. Condensation polymerization continues to receive intense academic and industrial attention for the preparation of polymeric materials used in a vast array of applications [46].…”

Section: Introductionmentioning

confidence: 99%

Advances in synthetic optically active condensation polymers - A review

Mallakpour

Zadehnazari²,

Iran³

2011

Express Polym. Lett.

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Abstract. The study of optically active polymers is a very active research field, and these materials have exhibited a number of interesting properties. Much of the attention in chiral polymers results from the potential of these materials for several specialized utilizations that are chiral matrices for asymmetric synthesis, chiral stationary phases for the separation of racemic mixtures, synthetic molecular receptors and chiral liquid crystals for ferroelectric and nonlinear optical applications. Recently, highly efficient methodologies and catalysts have been developed to synthesize various kinds of optically active compounds. Some of them can be applied to chiral polymer synthesis. In a few synthetic approaches for optically active polymers, chiral monomer polymerization has essential advantages in applicability of monomer, apart from both asymmetric polymerization of achiral or prochiral monomers and enantioselective polymerization of a racemic monomer mixture. The following are the up to date successful approaches to the chiral synthetic polymers by condensation polymerization reaction of chiral monomers.

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Polymers. III. Synthesis of Optically Active Stereoregular Polyolefins^1-3

Cited by 53 publications

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Stereospecific Polymerization

Stereospecific Polymerization

Chiral Polyolefins

Advances in synthetic optically active condensation polymers - A review

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Polymers. III. Synthesis of Optically Active Stereoregular Polyolefins1-3

Cited by 53 publications

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Stereospecific Polymerization

Stereospecific Polymerization

Chiral Polyolefins

Advances in synthetic optically active condensation polymers - A review

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Polymers. III. Synthesis of Optically Active Stereoregular Polyolefins^1-3