Palladium-Mediated Polymerization of Alkyl Diazoacetates To Afford Poly(alkoxycarbonylmethylene)s. First Synthesis of Polymethylenes Bearing Polar Substituents

Ihara, Eiji; Haida, Nobuyuki; Iio, Makoto; Inoue, Kenzo

doi:10.1021/ma021169v

Cited by 90 publications

(70 citation statements)

References 11 publications

(11 reference statements)

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“…[13][14][15] Die Veröffentlichung einer beispiellosen stereoselektiven Polymerisation von "Carbenen" aus Ethyldiazoacetat (EDA) zu einem hochmolekularen Poly(ethyl-2-ylidenacetat) (PEA; Schema 1 b mit X = H, Y = CO 2 Et) war kürzlich in dieser Hinsicht bahnbrechend. [ …”

Section: Die Stereokontrollierte Synthese Vonunclassified

Carbenchemie: stereoreguläre Polymere aus Diazoverbindungen

Noels

2007

Angewandte Chemie

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Section: Die Stereokontrollierte Synthese Vonunclassified

Carbenchemie: stereoreguläre Polymere aus Diazoverbindungen

Noels

2007

Angewandte Chemie

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“…But competing suggestions about the oxidation states of palladium during the catalytic process still exist. While Ihara and coworkers proposed the in situ generated Pd II -alkyl species as the active species, 3 de Bruin and coworkers supposed the involvement of low-valent Pd species (Pd 0 or Pd I ). 9 Even though the NMR spectra of the atactic polycarbenes suggests a radical polymerization mechanism, the involvement of free radical species was excluded.…”

Section: Introductionmentioning

confidence: 99%

Polymeric palladium-mediated carbene polymerization

Xiao

Liu

2015

Polym. Chem.

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Metalloenzyme-inspired polymeric palladium catalyst, which was prepared by self-assembly of polymeric imidazole ligand with PdCl 2 , promoted carbene polymerization with high catalytic activity and reusability. Besides the atactic polycarbethoxycarbene (PCEC), small amount of stereoregular PCEC was also obtained with poly(imidazole-Pd)-mediated polymerization of ethyl diazoacetate (EDA). This is the first example that stereoregular polycarbene in isolated form is obtained with a palladium-initiating system, suggesting that the steric polymeric imidazole ligand could affect the carbene insertion process. Detailed end group analyses on the obtained atactic and stereoregular PCEC revealed the chain initiation and chain termination mechanisms. XPS analyses on the oxidation state changes of palladium center exhibited that Pd II was reduced to Pd I , which suggests an intramolecular electron transfer process occurred during the interaction of palladium and EDA. Kinetic study showed a zero order kinetic dependent on the concentration of EDA, which indicates a strong binding of EDA on the catalyst preceding carbene formation. With the addition of radical inhibitor, the reaction rate was found to be greatly decreased. In the presence of spin trap, a striking electron paramagnetic resonance (EPR) spectrum could be detected, which suggests the involvement of radical intermediates. DFT calculations on the proposed Pd-carbene radical species supported the EPR analyses, which assigned a significant amount of spin density on the carbene-carbon atom. Based on these results, we proposed an unprecedented metal-carbene radical polymerization mechanism, which occurrs through a stepwise carbene radical migration and insertion process to afford polycarbene.Scheme 1 Poly(imidazole-Pd)-mediated polymerization of EDA to produce atactic and stereoregular PCEC.

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“…Pd-mediated Polymerization of Diazoacetylferrocene (1) and 1,1 0 -Bis(diazoacetyl)ferrocene (2) As a bifunctional diazocarbonyl compound which can be used for the synthesis of network polymers, we first chose 1,1 0 -bis(diazoacetyl)ferrocene (2). In order to check the reactivity of the diazoacetyl group of 2, we also examined the Pd-mediated polymerization of diazoacetylferrocene 1, monofunctional counterpart to 2.…”

Section: Resultsmentioning

confidence: 99%

Palladium-Mediated Polymerization of Bifunctional Diazocarbonyl Compounds: Preparation of Crosslinked Polymers by Copolymerization of Bi- and Monofunctional Diazocarbonyl Compounds

et al. 2009

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Pd-mediated copolymerization of bifunctional diazocarbonyl compounds, 1,1 0 -bis(diazoacetyl)ferrocene 2, 4,4 0 -bis(diazoacetyl)biphenyl 5, and bis(4-diazoacetylphenyl)dimethylsilane 6, with monofunctional diazoketones, (E)-1-diazo-3-nonen-2-one 3 and (E)-1-diazo-4-phenyl-3-buten-2-one 4, and ethyl diazoacetate 7 was examined in order to prepare a new type of crosslinked polymer. Although copolymerization of 2 with 3 and 4 proceeded in the presence of PdCl 2 (MeCN) 2 , the products were soluble in CHCl 3 and their M n s were rather low irrespective of the feed ratio of the comonomers, probably because of the occurrence of intramolecular cyclization of two diazoacetyl groups in 2. On the other hand, copolymerization of 5 and 6 with 3, 4, and 7 with relatively high feed ratios of the bifunctional monomers afforded products insoluble in CHCl 3 , which suggested the formation of crosslinked polymers. In addition, Pd-mediated (co)polymerization of monofunctional diazoacetylferrocene 1, monofunctional counterpart to 2, was examined, resulting in the formation of a new type of ferrocene-containing polymer.KEY WORDS: Copolymerization / Crosslinking / Network Polymer / Bis(diazocarbonyl) Compound / Recently, we and other groups have been developing polymerization of diazocarbonyl compounds, that can afford a new type of C-C main chain polymer bearing carbonylcontaining substitutents on its all the main chain carbon atoms. Cu-, 1 Pd-, 2 Rh-, 3,4 and B-mediated 5 polymerization and oligomerization have been reported for alkyl diazoacetate, which is the most common type of diazocarbonyl compound.

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Palladium-Mediated Polymerization of Alkyl Diazoacetates To Afford Poly(alkoxycarbonylmethylene)s. First Synthesis of Polymethylenes Bearing Polar Substituents

Cited by 90 publications

References 11 publications

Carbenchemie: stereoreguläre Polymere aus Diazoverbindungen

Carbenchemie: stereoreguläre Polymere aus Diazoverbindungen

Polymeric palladium-mediated carbene polymerization

Palladium-Mediated Polymerization of Bifunctional Diazocarbonyl Compounds: Preparation of Crosslinked Polymers by Copolymerization of Bi- and Monofunctional Diazocarbonyl Compounds

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