Inclusion polymerization of diene and diacetylene monomers in deoxycholic acid and apocholic acid canals

Miyata, Mikiji; Noma, Fusaharu; Okanishi, Ken; Tsutsumi, Hiromori; Takemoto, Kiichi

doi:10.1007/bf00655658

Cited by 10 publications

(1 citation statement)

References 11 publications

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“…These studies were followed by the asymmetric polymerization of similar trans-and cis-1,3-pentadienes within the channels of two steroids of deoxycholic acid (DCA) and apocholic acid (ACA) [12][13][14]. The packing of the two [16].…”

Section: ''Through-space'' Asymmetric Polymerization In Inclusion Commentioning

confidence: 99%

“Absolute” Asymmetric Polymerization within Crystalline Architectures: Relevance to the Origin of Homochirality

Weissbuch

Lahav

2012

Materials Science and Technology

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The emergence of the homochiral proteins and nucleic acids, composed from residues of L-amino acids and D-sugars respectively, from the achiral prebiotic world still provides an unsolved conundrum in the field of the origin of life. This mist results from the fundamental symmetry rules as defined, at the end of the nineteenth century, by the Curie principle [1], which states that, '' . . . a physical event cannot have a symmetry lower than that of the event that caused it.''There are two classes of asymmetric transformation, which are in keeping with this symmetry rule. In the first class, chiral reactants are converted, via chemical reactions, into chiral products; in the second class, ''mirror-symmetry'' can be broken spontaneously in either a single or a small number of chemical reactions. In a large number of related independent events, however, the system will preserve its initial nonchiral symmetry. Such class of stochastic asymmetric transformations might have been relevant to chiro-biogenesis, provided the scenario can be accepted that life started in a small number of locations, and that the handedness generated by chance has been amplified and propagated during a competition with heterochiral architectures, such that one of the homochiral architectures has tripped and the other has won the rivalry [2][3][4][5].In this chapter, the second class of stochastic asymmetric synthesis of polymers -referred to as ''absolute'' asymmetric synthesis -and which has been materialized in laboratory experiments, is described. Several successful systems of ''mirror-symmetry breaking'' have been shown to comprise the following steps: spontaneous self-assembly of molecules into crystalline-like supramolecular architectures that create a local homochiral molecular environment exerting asymmetric induction in the ensuing propagation of the polymerization reaction. Farina [6] coined the term ''through-space'' asymmetric transformations in order to distinguish them from the common ''through-bond'' reactions.Here, attention is confined especially to the asymmetric transformations of achiral monomers within crystalline or quasi-crystalline architectures. In particular, the early studies of asymmetric polymerizations performed within enantiomorphous

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Section: ''Through-space'' Asymmetric Polymerization In Inclusion Commentioning

confidence: 99%

“Absolute” Asymmetric Polymerization within Crystalline Architectures: Relevance to the Origin of Homochirality

Weissbuch

Lahav

2012

Materials Science and Technology

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Functional monomers and polymers, 163. Inclusion polymerization of cyclic diene monomers in deoxycholic acid canals

Tsutsumi

Miyata

Takemoto

1989

Angew. Makromol. Chem.

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Inclusion polymerization of cyclic diene monomers, such as cyclopentadiene, 1,3cyclohexadiene, 1,3-~ycloheptadiene, 1,5-cyclooctadiene, and 2,5-norbornadiene, was studied, using deoxycholic acid (DCA) as the canal component.The formation of monomer-DCA adducts was observed, however, the polymerization occurred only in the case of cyclopentadiene, 1,3-cyclohexadiene, or 1,3-cycloheptadiene. The polymers obtained consisted preferably of 1,4-units and almost 100% of 1 ,4-units in the case of 1,3-cyclohexadiene. ESR measurements revealed that inclusion polymerization of cyclopentadiene or 1,3-cyclohexadiene in DCA canals proceeds by a free radical mechanism. ZUSAMMENFASSUNG:Mit Desoxycholslure (DCS) als Wirtskomponente wird die EinschluBpolymerisation von cyclischen Dienmonomeren wie Cyclopentadien, 1,3-Cyclohexadien, 1,3-Cycloheptadien, 1,5-Cyclooctadien und 2,5-Norbornadien untersucht. Die Bildung von Monomer-DCS-EinschluRverbindungen wurde beobachtet, aberPolymerisation setzte nur mit Cyclopentadien, 1,3-Cyclohexadien oder 1,3-Cycloheptadien ein. Die erhaltenen Polymeren bestanden hauptsachlich aus 1,4-Einheiten und fast zu 100% aus 1 ,CEinheiten im Fall des 1,3-Cyclohexadiens. ESR-Messungen zeigen, daB die EinschluBpolymerisation von Cyclopentadien oder 1,3-Cyclohexadien in DCS-Kanalen nach einem Radikal-Mechanismus ablauft .

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Functional monomers and polymers, 157. Inclusion polymerization of 1,3‐butadiene derivatives with bulky substituents in deoxycholic acid and apocholic acid canals

Miyata

Tsuzuki

Takemoto

1987

Makromol. Chem., Rapid Commun.

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Inclusion polymerization of diene and diacetylene monomers in deoxycholic acid and apocholic acid canals

Cited by 10 publications

References 11 publications

“Absolute” Asymmetric Polymerization within Crystalline Architectures: Relevance to the Origin of Homochirality

“Absolute” Asymmetric Polymerization within Crystalline Architectures: Relevance to the Origin of Homochirality

Functional monomers and polymers, 163. Inclusion polymerization of cyclic diene monomers in deoxycholic acid canals

Functional monomers and polymers, 157. Inclusion polymerization of 1,3‐butadiene derivatives with bulky substituents in deoxycholic acid and apocholic acid canals

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