Novel Initiators Having Acetylene Group for Polymerization of 2-Oxazolines

Kobayashi, Shiro; Uyama, Hiroshi; Mori, Toshild; Narita, Yutaka

doi:10.1246/cl.1991.1771

Cited by 12 publications

(4 citation statements)

References 7 publications

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“…The most‐studied initiators have alkyl chains of various lengths,22, 36, 37, 47–49 as well as perfluorinated chains 28, 50. Compatibility also exists with unsaturated aliphatic initiators with double51–53 or triple bonds,34, 54, 55 even if transfer reactions appear above 50% conversion in the latter case. These unsaturated groups are of interest because they can be involved in two types of “click” reaction: thiol‐ene coupling (TEC) and copper‐catalyzed azide‐alkyne cycloaddition (CuAAC), named Huisgen's cycloaddition.…”

Section: Initiator‐based Functionalizationmentioning

confidence: 99%

“…Macroinitiators deriving from cholesteryl56 and vegetable oils, such as castor oil,57 diacylglycerol,56 and 1,2‐ o ‐diooctadecyl‐ sn ‐glyceryl48 are employed in the synthesis of amphiphilic copolymers. The CROP of 2‐oxazoline is also compatible with bis‐initiators bearing unsaturated moieties, like acetylenic groups55, 60 and double bonds 52, 61, 62. Multifunctional initiators based on alkyl chains,61, 63, 64 aromatic rings with two reactive sites in the ortho, meta or para positions52 or six reactive sites65 are used in the elaboration of more‐complex structures.…”

Section: Initiator‐based Functionalizationmentioning

confidence: 99%

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How to Modulate the Chemical Structure of Polyoxazolines by Appropriate Functionalization

Guillerm¹,

Monge²,

Lapinte³

et al. 2012

Macromol. Rapid Commun.

203

171

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Polyoxazolines (POx) are increasingly studied as polymeric building blocks due to the possibility of affording tunable properties. Additionally, as it was proved that biocompatibility and stealth behavior of POx are similar to that of poly(ethylene glycol) (PEG), it became challenging to develop polyoxazoline-based (co)polymers. Even if POx have a lot of advantages, they also show an important drawback as it is to date impossible to prepare high molecular weight polyoxazolines, with low polydispersity indexes. So, it appears important to judiciously functionalize them. This review covers the multiple ways of functionalization of polyoxazolines.The use of functional initiators, functional terminating agents, and 2-R-2-oxazolines with R functional side group is detailed. In conclusion, some perspectives on POxfunctionalizations are also reported, with functions permitting selective "click" reactions.

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Section: Initiator‐based Functionalizationmentioning

confidence: 99%

Section: Initiator‐based Functionalizationmentioning

confidence: 99%

How to Modulate the Chemical Structure of Polyoxazolines by Appropriate Functionalization

Guillerm¹,

Monge²,

Lapinte³

et al. 2012

Macromol. Rapid Commun.

203

171

View full text Add to dashboard Cite

show abstract

“…[5,6] For example, Yb(OTf )3, a representative lanthanide triflate, was revealed to have superior performance in the Mukaiyama aldol reactions of not only benzaldehyde 1a but also aqueous formaldehyde 1s (for all aldehydes 1, see Figure 1) with silicon enolate 2a (for all silicon enolates 2, see Figure 1) in water-THF (Scheme 1). [4] The reactions also proceeded well in a water-ethanol-toluene cosolvent system. [7] The conventional problem that Lewis acids decompose in the presence of water was thus overcome using rare-earth triflates (Sc(OTf )3, [8] Y(OTf )3, Ln(OTf )3).…”

Section: Highlightsmentioning

confidence: 89%

“…[3] Facile, convenient, and environmentally benign methodologies without tedious operation are desirable. The discovery of water-compatible Lewis acids in 1991 [4] contributed significantly to an explosive advance in this field. A major difficulty in the construction of asymmetric environments in aqueous conditions is the weakness of noncovalent interactions between substrates, chiral ligands, and metal ions under competitive polar conditions.…”

Section: Introductionmentioning

confidence: 99%

Development of Chiral Catalysts for Mukaiyama Aldol Reactions in Aqueous Media

Kitanosono

Kobayashi

2014

The Chemical Record

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Since the discovery of the Mukaiyama aldol reaction in 1973, tremendous efforts have been made to develop a definitive catalyst that catalyzes asymmetric Mukaiyama aldol reactions under mild conditions with broad substrate tolerance. Forty years later, an exhaustive search for a water-compatible Lewis acid was able to uncover the hidden potential of iron(II) and bismuth(III), leading to the establishment of broadly applicable and versatile catalytic systems for asymmetric Mukaiyama aldol reactions in aqueous media. The ternary catalytic system was able to expand the substrate generality considerably as the most distinguished catalyst ever reported. The superiority of this methodology over conventional methods has also been demonstrated in terms of high catalytic activity, simplicity of experimental procedures, and a wide substrate range including aqueous aldehydes, for which the stereochemistry had been regarded as difficult to control. Furthermore, a facile synthesis of the chiral ligand underscores its versatility. The reaction did not proceed at all without use of water. In the postulated mechanism, water plays prominent roles in: (1) producing the active metal complexes with a high water-exchange rate constant (3.2 × 10(6)) to activate substrates effectively and to catalyze the reaction through a rapid proton transfer on the order of picoseconds; (2) facilitating the catalytic turnover with simultaneous desilylation as direct access to aldol adducts or facile recovery of active metal complexes; and (3) stabilizing rigid transition states composed of metal complexes and reactants through entropy-driven aggregation derived from the highest cohesive energy density.

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Poly(2‐oxazoline)s

Verbraeken

Lava

Hoogenboom

2014

Encyclopedia of Polymer Science and Technology

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Research in the field of poly(2‐oxazoline)s (PAOx) is rapidly expanding as this polymer class combines high synthetic versatility and biocompatibility, opening up the way to highly functional (biocompatible) materials. PAOx are prepared by living cationic ring‐opening polymerization (CROP) of 2‐oxazolines. The variety of 2‐oxazoline monomers that are readily available or can easily be synthesized allows for tuning of polymer properties and introduction of diverse functionalities. Moreover, thanks to the living nature of CROP, well‐defined polymers with narrow molar mass distribution and high end group fidelity can be obtained. This article covers all aspects of PAOx ranging from the synthesis of 2‐oxazoline monomers, via in‐depth discussion on the CROP mechanism to the synthesis and properties of functional PAOx (co)polymers. The presented research demonstrates that owing to their structural adaptability and the so‐called “stealth” behavior, PAOx are well suited for a range of biomedical applications, including polymer therapeutics, scaffolds for three‐dimensional cell culture, surface modification, matrix excipient for solid dispersions, and antimicrobial agents.

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Novel Initiators Having Acetylene Group for Polymerization of 2-Oxazolines

Cited by 12 publications

References 7 publications

How to Modulate the Chemical Structure of Polyoxazolines by Appropriate Functionalization

How to Modulate the Chemical Structure of Polyoxazolines by Appropriate Functionalization

Development of Chiral Catalysts for Mukaiyama Aldol Reactions in Aqueous Media

Poly(2‐oxazoline)s

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