ROMP of Norbornene Monomers Carrying Nonprotected Amino Groups with Ruthenium Catalyst

Sutthasupa, Sutthira; Sanda, Fumio; Masuda, Toshio

doi:10.1021/ma802243e

Cited by 36 publications

(53 citation statements)

References 34 publications

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“…Interestingly however, amino acid-derived exo,exo-norbornene monomer 31 (Scheme 20) having unprotected methylamino groups undergoes ROMP to give the polymer in good yield. 66 The key for successful polymerization is the presence of appropriate spacers between the amino groups and the norbornene skeleton, and possibly intramolecular hydrogen bonding between the amino and carbonyl groups, which presumably prevents the amino groups from deactivating the catalyst. The methyl groups at the nitrogen atoms are also important, because analogous monomer 32 having primary amino groups shows Scheme 21 Possible regular structures of poly(endo,endo-2,3-disubstituted norbornene) (left) and poly(exo,exo-2,3-disubstituted norbornene) (right): R*, chiral group; H A and H B , two sets of nonequivalent olefinic protons distinguishable by 1 H nuclear magnetic resonance spectroscopy.…”

Section: Recent Advances In Rompmentioning

confidence: 99%

“…Spectroscopic analysis by 1 H-1 H correlated spectroscopy nuclear magnetic resonance revealed that the polymer of 31 is syndiotactic-rich. 66 Molecular mechanics simulation suggested that this selectivity is kinetically caused by stability of metallacyclobutane intermediates rather than the thermodynamical stability of the product structures.…”

Section: Recent Advances In Rompmentioning

confidence: 99%

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Recent advances in ring-opening metathesis polymerization, and application to synthesis of functional materials

Sutthasupa

Shiotsuki

Sanda

2010

Polym J

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339

273

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This article reviews the development of catalysts for ring-opening metathesis polymerization (ROMP), synthesis of polymers bearing amino acids and peptides by ROMP of functionalized norbornenes, formation of aggregates and micelles, and applications of the polymers to medical materials. It also describes the control of monomer unit sequences, that is, living polymerization to synthesize block copolymers, and alternating copolymerization that is achieved on the basis of acid-base interactions. Polymer Journal (2010) 42, 905-915; doi:10.1038/pj.2010.94; published online 13 October 2010Keywords: alternating copolymerization; amino acid; block copolymerization; living polymerization; metathesis catalyst; peptide; ROMP INTRODUCTIONOlefin metathesis reactions are metal-mediated carbon-carbon (C-C) double bond exchange processes, 1,2 which were discovered in the mid 1950s. Chauvin proposed the commonly accepted mechanism for metathesis involving a metallacyclobutane, as illustrated in Scheme 1. 3 Initially, olefin metathesis was regarded as an odd reaction, but now it has undoubtedly established the position as one of the most important C-C bond formation reactions applicable to synthesis of a wide variety of useful products. In the early stages, transition metal chlorides were used as catalysts for the reaction, but the transition metal carbene complex catalysts designed by Schrock and Grubbs have remarkably advanced mechanistic analysis and control of catalytic activity by the choice of ligands. In 2005, Chauvin, Grubbs and Schrock were awarded the Nobel Prize in chemistry for development of the metathesis method in organic synthesis.Olefin metathesis polymerization is an application of metathesis reactions to polymer synthesis and includes ring-opening metathesis polymerization (ROMP) and acyclic diene metathesis (ADMET) polycondensation (Scheme 2). ADMET has been extensively developed by Wagener since 1987 4 for the synthesis of polyolefins having regularly spaced functional group branches and high thermal stability and crystallinity. 5,6 ADMET is also useful for synthesizing polymeric materials containing in-chain functionality. Although the general structures of the polymers obtained by ROMP and ADMET are illustratable in the same fashion as shown in Scheme 2, a completely different treatment is necessary from the viewpoint of polymerization kinetics. The former involves chain polymerization, whereas the latter is a step-growth polymerization process.

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Section: Recent Advances In Rompmentioning

confidence: 99%

Section: Recent Advances In Rompmentioning

confidence: 99%

Recent advances in ring-opening metathesis polymerization, and application to synthesis of functional materials

Sutthasupa

Shiotsuki

Sanda

2010

Polym J

Self Cite

339

273

View full text Add to dashboard Cite

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“…With monomer M1 in hand, ROMP with commercially available second-generation Grubbs catalyst was attempted. Using conditions modified from ROMP of amino acid-derived monomers, 21 we began by stirring a solution of M1 and 1 mol % Ru catalyst in THF at room temperature. The progress of the reaction was monitored by taking aliquots and evaluating by NMR spectroscopy.…”

Section: ■ Introductionmentioning

confidence: 99%

“…It was determined that 20 h was required to reach full conversion, and this prolonged reaction time (in comparison to ROMP with unfunctionalized monomers, see Supporting Information) was consistent with previous reports of ROMP with amine-containing monomers. 21 After quenching with ethyl vinyl ether and adding cold hexanes, a white solid was precipitated and isolated in quantitative yield (Table 1, entry 1). Analysis of the polymeric product by 1 H NMR spectroscopy shows characteristic broadening of signals typical of polymeric material.…”

Section: ■ Introductionmentioning

confidence: 99%

Catalytic Synthesis of Secondary Amine-Containing Polymers: Variable Hydrogen Bonding for Tunable Rheological Properties

Perry¹,

Ebrahimi

Morgan³

et al. 2016

Macromolecules

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A synthetic protocol using atom-economic, catalytic hydroaminoalkylation and ring-opening metathesis polymerization (ROMP) has been developed for the versatile synthesis of a new class of aryl-substituted secondary aminecontaining polymers. This catalytic route minimizes waste generation and avoids protection/deprotection protocols, postpolymerization modification, and byproduct formation. Different amines can be readily incorporated to access variable hydrogen-bonding characteristics. Thermal and melt rheological characterization has shown the profound effect of hydrogen bonding on the bulk properties of these amine-containing norbornene polymers. ■ INTRODUCTIONThere is growing interest in developing approaches to synthesize amine-containing polymers due to their diverse range of applications including antimicrobial materials, 1−5 compatibilizers for polymer blends, 6−8 CO 2 uptake, 9−11 water purification, 12,13 and catalytic materials. 14−20 Current strategies for the synthesis of these high-value products are often plagued by multistep monomer syntheses with inefficient protection/ deprotection protocols 1,21−23 and/or the use of postpolymerization modifications. 24,25 These traditional routes often result in limited control over amine functionalization and poorly defined polymer microstructures. 26 In recent years, ROMP 20 has emerged as a powerful tool for the synthesis of functionalized polymers including polyamides. 27−30 Notably, ROMP conditions rarely tolerate free primary or secondary pendant amine groups, 31,32 presumably due to the fact that these nucleophilic and sterically accessible amines can coordinate and decompose catalytic Ru species. 33 More recently, select norbornene monomers with tertiary or secondary alkylamines have been shown to undergo ROMP using a newly reported cationic Mo alkylidene metathesis catalyst. 34 However, these reports involve multistep synthetic protocols and stoichiometric reagents to access the requisite norbornene substrates. Thus, to date, the controlled polymerization of unprotected amine-containing monomers has not been a practical and efficient strategy for accessing this broadly useful class of materials.Our approach for addressing synthetic challenges in aminecontaining polymer synthesis exploits our recently developed hydroaminoalkylation catalysts, 35,36 coupled with promising results in ROMP of functionalized monomers (Scheme 1). 37 Hydroaminoalkylation is an α-C−H alkylation reaction of secondary amines with alkene substrates. 36 By using our N,Ochelated tantalum phosphoramidate precatalyst 1, 35 amine functionalized, cyclic alkene monomers can be prepared in one solvent-free, atom-economic reaction of cyclic diene precursors (Scheme 2). Thus, these two catalytic strategies can be combined to access a flexible and modular synthetic approach while realizing optimized atom and step efficiency. Importantly, hydroaminoalkylation yields unprotected secondary amines that participate in hydrogen bonding to give amine-containing polymers with tunable physical and me...

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“…34,35 For example, ring-opening metathesis polymerization (ROMP) was successfully employed to prepare a range of amino acid-functionalized homopolymers and block copolymers. [36][37][38] With regard to controlled radical polymerization formulations, atom transfer radical polymerization can be used to prepare similar copolymers. 39 However, reversible addition-fragmentation chain transfer (RAFT) polymerization seems to be preferred for such syntheses, presumably because of its superior tolerance of carboxylic acid functionality.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of poly(amino acid methacrylate)-stabilized diblock copolymer nano-objects

et al. 2015

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International audienceAmino acids constitute one of Nature's most important building blocks. Their remarkably diverse properties (hydrophobic/hydrophilic character, charge density, chirality, reversible cross-linking etc.) dictate the structure and function of proteins. The synthesis of artificial peptides and proteins comprising main chain amino acids is of particular importance for nanomedicine. However, synthetic polymers bearing amino acid side-chains are more readily prepared and may offer desirable properties for various biomedical applications. Herein we describe an efficient route for the synthesis of poly(amino acid methacrylate)-stabilized diblock copolymer nano-objects. First, either cysteine or glutathione is reacted with a commercially available methacrylate-acrylate adduct to produce the corresponding amino acid-based methacrylic monomer (CysMA or GSHMA). Well-defined water-soluble macromolecular chain transfer agents (PCysMA or PGSHMA macro-CTAs) are then prepared via RAFT polymerization, which are then chain-extended via aqueous RAFT dispersion polymerization of 2-hydroxypropyl methacrylate. In situ polymerization- induced self-assembly (PISA) occurs to produce sterically-stabilized diblock copolymer nano-objects. Although only spherical nanoparticles could be obtained when PGSHMA was used as the sole macro-CTA, either spheres, worms or vesicles can be prepared using either PCysMA macro-CTA alone or binary mixtures of poly(glycerol monomethacrylate) (PGMA) with either PCysMA or PGSHMA macro-CTAs. The worms formed soft free-standing thermo-responsive gels that undergo degelation on cooling as a result of a worm-to-sphere transition. Aqueous electrophoresis studies indicate that all three copolymer morphologies exhibit cationic character below pH 3.5 and anionic character above pH 3.5. This pH sensitivity corresponds to the known behavior of the poly(amino acid methacrylate) steric stabilizer chains

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ROMP of Norbornene Monomers Carrying Nonprotected Amino Groups with Ruthenium Catalyst

Cited by 36 publications

References 34 publications

Recent advances in ring-opening metathesis polymerization, and application to synthesis of functional materials

Recent advances in ring-opening metathesis polymerization, and application to synthesis of functional materials

Catalytic Synthesis of Secondary Amine-Containing Polymers: Variable Hydrogen Bonding for Tunable Rheological Properties

Synthesis and characterization of poly(amino acid methacrylate)-stabilized diblock copolymer nano-objects

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