نتایج جستجو برای: norbornene
تعداد نتایج: 529 فیلتر نتایج به سال:
The first palladium-catalyzed ring opening of norbornene to prepare methylenecyclopentane derivatives has been established. The process, which uses readily available aryl iodides, tosylhydrazones and norbornene as starting materials, likely takes place via tandem Heck-type coupling, palladium carbene migratory insertion, C-C bond cleavage and the β-hydride elimination pathway in a single synthe...
Phosphino-phenolate neutral nickel catalysts 1-3/B(C6F5)3, without the help of any organoaluminum compound, were found to be efficient catalytic systems for norbornene polymerization and its copolymerization with norbornene derivatives. The amount of B(C6F5)3 required for achieving a high efficiency (3 equiv.) was markedly lower compared to previous reports, and high molecular weight polymers w...
The Carboni-Lindsey reaction between tetrazines and strained unsaturated hydrocarbons has in recent years become a useful tool bioorthogonal chemistry for labelling biomolecules vitro vivo. Here, we report computational studies on the mechanism of Diels-Alder/Retro-Diels-Alder commercially available tetrazine norbornene. Isomerism with norbornene-amide relevant applications bioconjugation chemi...
highly active metallocenes and other single site catalysts have opened up the possibility of polymerizing cycloolefins such as norbornene (n) or of copolymerizing them with ethene (e) or propene (p). the polymers obtained show exciting structures and properties. e-n copolymers are industrially produced materials, with variable and high glass transitions depending on the wide range of their micr...
Ring-opening metathesis polymerization (ROMP) of norbornene (NB) and its derivatives N-adamantyl-exoendo-norbornene-5,6-dicarboximide (AdNDI) and N-cyclohexyl-exo-endo-norbornene-5,6-dicarboximide (CyNDI) in the presence of cis-1,4-dichloro-2-butene (2a) and cis-1,2-dichloro-ethylene (2b) as chain transfer agents (CTAs) using a [1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazolilydene] (PCy3)C...
Highly active metallocenes and other single site catalysts have opened up the possibility of polymerizing cycloolefins such as norbornene (N) or of copolymerizing them with ethene (E) or propene (P). The polymers obtained show exciting structures and properties. E-N copolymers are industrially produced materials, with variable and high glass transitions depending on the wide range of their micr...
The oxidative addition of cyclic ditelluride 1-oxa-5,6-ditelluraspirooctane, Te(2)C(5)H(8)O, to bis(triphenylphosphine)(norbornene)platinum(0), [Pt(PPh(3))(2)(eta(2)-nb)], and to [1,8-bis(diphenylphosphino)naphthalene](norbornene)platinum(0), [Pt(dppn)(eta(2)-nb)], lead to the formation of dinuclear and mononuclear tellurolato platinum(ii) complexes, respectively, as a consequence of Te-Te bond...
The scope of the Pauson-Khand reaction (PKR) of internal trifluoromethyl alkynes, previously described with norbornadiene, is expanded to norbornene and ethylene. A thorough structural analysis of the resulting PK adducts has been carried out to unveil that α-trifluoromethylcyclopentenones are preferred in all cases, independently of the electronic properties of the alkyne. The regioselectivity...
A new strategy is presented for the synthesis of graft copolymers using only the ring-opening metathesis polymerization (ROMP). From a ROMP-derived main chain, pendant maleimide functional groups are converted into norbornene moieties via a Diels-Alder reaction with cyclopentadiene. The norbornene groups serve as sites of initiation, and subsequent ROMP from the main chain yields graft copolyme...
The C-C coupling of N,N'-bis(5-norbornene-2,3-dicarboximide) (3) and N,N'-bis(7-oxa-5-norbornene-2,3-dicarboximide) (6) with aryl and heteroaryl iodides gave under reductive Heck conditions the C-aryl(hetaryl), substituted N,N'-bistricyclic imides 7a-f and 8a,b. The fused spiro-1,3-indandionolylpyrrolidine compounds, 9, 10 and 11 were also obtained from ninhydrine, sarcosine and 3 or 6 via [3+2...
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