Dynamic Covalent Chemistry in Rotaxane Synthesis. Slipping Approach to [2]Rotaxane Utilizing Reversible Cleavage–Rebondage of Trityl Thioether Linkage

Furusho, Yoshio; Oku, Tomoya; Rajkumar, G. Abraham; Takata, Toshikazu

doi:10.1246/cl.2004.52

Cited by 23 publications

(9 citation statements)

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“…20 Since disulfide bonding is labile, and disulfide-exchange reaction is catalyzed by the certain nucleophile such as thiol, a few wonderful methods to prepare rotaxanes based on the dynamic covalent chemistry are developed by Takata et al [21][22][23] When a bifunctional secondary ammonium salt bearing disulfide linkage and bulky end-caps was mixed with dibenzo-24-crown-8 and a catalytic amount of benzenethiol, crown ether entered into the T. TAKATA disulfide linkage to afford [2] and [3]rotaxanes 21,22 (Scheme 6). The mechanism of the formation of these rotaxanes is simply illustrated in Scheme 7, which is so called ''unlock-lock'' process.…”

Section: Dynamic Covalent Bond Chemistry In Rotaxane Synthesismentioning

confidence: 99%

“…As depicted in Scheme 6, a mixture of DB24C8 wheel and an axle component having central sec-ammonium group and terminal trityl sulfide group is treated with trifluoroacetic acid in the presence of trace amount of water to afford corresponding [2]rotaxane in $97% yield. 23 Reversible C-S bond cleavage gives rise to the high yielding preparation of rotaxane. …”

Section: Dynamic Covalent Bond Chemistry In Rotaxane Synthesismentioning

confidence: 99%

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Polyrotaxane and Polyrotaxane Network: Supramolecular Architectures Based on the Concept of Dynamic Covalent Bond Chemistry

Takata

2006

Polym J

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ABSTRACT:This review article concerns with the syntheses of polyrotaxanes and polyrotaxane networks that can be constructed mainly on the basis of the concept of dynamic covalent bond chemistry. At the beginning of the review, synthetic methods of rotaxanes are briefly summarized along with several high yielding preparations. Synthesis of poly- [3]rotaxane by the reaction of homoditopic monomers utilizing the thiol-disulfide interchange reaction was discussed in detail, among polyrotaxanes possessing topological bonds for the monomer linking in the main chain. Polyrotaxane network was prepared by a similar protocol from a polyfunctional crown ether and a dumbbell-shaped homoditopic axle containing two sec-ammonium salt moieties and centrally located disulfide bond. Some characteristics of the polyrotaxane network were demonstrated, including the recyclable property as the crosslinked polymer. The meaning and applicability of the reversible crosslinking/decrosslinking system developed in the polyrotaxane network are specially emphasized for unique and potential application.

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Section: Dynamic Covalent Bond Chemistry In Rotaxane Synthesismentioning

confidence: 99%

Section: Dynamic Covalent Bond Chemistry In Rotaxane Synthesismentioning

confidence: 99%

Polyrotaxane and Polyrotaxane Network: Supramolecular Architectures Based on the Concept of Dynamic Covalent Bond Chemistry

Takata

2006

Polym J

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“…Stoddart and co-workers used reversible imine bond-formation and other methods to construct socalled dynamic [2]rotaxanes. [40][41][42] Takata and co-workers reported the thermodynamic synthesis of rotaxanes based on reversible tritylative endcapping of pseudorotaxanes having thiol or hydroxyl functionality 43,44 and reversible thiol-disulfide reactions. 45,46 Similar work with endcapping was published Tokunaga et al 47 In the present work, new hydroxyl-functionalized secondary ammonium salts were synthesized and complexed with dibenzo-24-crown-8 to form semirotaxanes and thence converted to [2]rotaxanes.…”

Section: Introductionmentioning

confidence: 99%

Semirotaxanes and unsymmetrical rotaxanes from substituted benzylammonium salts and dibenzo-24-crown-8

Niu¹,

Fletcher²,

Slebodnick³

et al. 2021

Arkivoc

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Three new hydroxyl-functionalized secondary benzyl ammonium salts were synthesized and complexed with dibenzo-24-crown-8. Three [2]semirotaxanes and then their two [2]rotaxanes each with two different stoppers were prepared successfully by reactions of the hydroxyl groups with bulky reagents. X-ray analysis of a single crystal of a [2]semirotaxane confirmed its structure. The formation of the [2]semirotaxanes can be reversibly controlled by adding KPF6 and 18-crown-6 sequentially. These new unsymmetrical [2]rotaxanes afford a way to prepare planar chiral rotaxanes and related supramolecular systems.

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“…On the other hand, successful applications of reversible covalent chemistry have been seen in the development of dynamic combinatorial libraries, [8][9][10][11][12][13][14] interlocked molecules, [15][16][17][18][19][20][21] drug discovery 22 and controlled release of fragrances. 23 Rowan et al 24 introduced the concept of dynamic covalent chemistry, which offered the possibility of 'doing supramolecular chemistry' at the level of covalent bonds.…”

Section: Introductionmentioning

confidence: 99%

Reorganization of polymer structures based on dynamic covalent chemistry: polymer reactions by dynamic covalent exchanges of alkoxyamine units

Otsuka

2013

Polym J

114

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The recent progress of research on polymer reactions utilizing dynamic covalent exchanges of alkoxyamine units-adducts of styryl and stable nitroxide radicals-is reviewed. The alkoxyamine derivatives derived from 2,2,6,6-tetramethylpiperidine-1-oxy (TEMPO, a stable free radical) are frequently utilized as unimolecular initiators for the nitroxide-mediated radical polymerizations. In the absence of monomers, however, the alkoxyamine derivatives can undergo intermolecular crossover reactions via a radical process upon heating. The central CON bonds in the alkoxyamine derivatives reversibly cleave and reform upon heating, and a mixture of alkoxyamine derivatives is able to equilibrate thermally, meaning that the covalent bonds in the alkoxyamine derivatives are considered as 'dynamic covalent bonds.' Unlike conventional polymers, the structures and constitutions of polymers with dynamic covalent bonds, dynamic covalent polymers, can be reorganized under appropriate conditions even after polymerization. In the present review, various types of macromolecular design, polymer reactions based on dynamic covalent exchanges of alkoxyamine units and their related research are described. Various examples of polymer reactions of main-chain-type, side-chain-type, crosslinked and star-shaped poly(alkoxyamine)s are systematically shown. Furthermore, the progress of the polymer reactions can be confirmed by diverse characterization techniques, such as spectroscopic, chromatographic, microscopic and scattering methods.

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Dynamic Covalent Chemistry in Rotaxane Synthesis. Slipping Approach to [2]Rotaxane Utilizing Reversible Cleavage–Rebondage of Trityl Thioether Linkage

Abstract: A [2]rotaxane was synthesized in a high yield from a dumbbell-shaped sec-ammonium salt having trityl thioether and 3,5-di-t-butylphenyl groups at the both ends and dibenzo-24-crown-8-ether, through the slipping, utilizing the reversible cleavage–rebondage of the trityl thioether linkage.

Cited by 23 publications

References 11 publications

Polyrotaxane and Polyrotaxane Network: Supramolecular Architectures Based on the Concept of Dynamic Covalent Bond Chemistry

Polyrotaxane and Polyrotaxane Network: Supramolecular Architectures Based on the Concept of Dynamic Covalent Bond Chemistry

Semirotaxanes and unsymmetrical rotaxanes from substituted benzylammonium salts and dibenzo-24-crown-8

Reorganization of polymer structures based on dynamic covalent chemistry: polymer reactions by dynamic covalent exchanges of alkoxyamine units

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