Showing papers on "Norbornene published in 2014"
TL;DR: This approach involves a palladium-catalyzed, norbornene-mediated ortho-amination/N-tosylhydrazone insertion reaction, which results inortho-Aminated vinylarene derivatives obtained via a reaction of aryl iodides, N-benzoyloxyamines, and N-toshydrazones.
Abstract: ortho-Aminated vinylarene derivatives were obtained via a reaction of aryl iodides, N-benzoyloxyamines, and N-tosylhydrazones. This approach involves a palladium-catalyzed, norbornene-mediated ortho-amination/N-tosylhydrazone insertion reaction. In this transformation, one C–N bond and one C–C bond are formed and an amine group is introduced at the ortho position successfully.
89 citations
TL;DR: In this paper, the transport properties of poly(trimethylsilyl propyne) and other polyacetylenes showed that similar properties can be revealed in glassy polymers, and the most important properties are reduction of the permeability of light components (CH4) in the presence of more condensable penetrant (C4H10) and higher selectivity of mixture separation as compared with ideal separation factors measured in the experiments with pure gases.
82 citations
TL;DR: The first nickel(0)-catalyzed [2 + 2 + 1] carbonylative cycloaddition reaction of imines and alkynes or norbornene has been achieved by employing phenyl formate as a CO source.
Abstract: The first nickel(0)-catalyzed [2 + 2 + 1] carbonylative cycloaddition reaction of imines and alkynes or norbornene has been achieved by employing phenyl formate as a CO source. With this method, a variety of N-benzenesulfonyl, -tosyl, and -phosphoryl-substituted γ-lactams can be prepared in good to high yields.
81 citations
TL;DR: A novel palladium-catalyzed norbornene-mediated three-component reaction for the construction of ortho-alkenyl aromatic tertiary amines has been achieved, which represents a useful extension of the Catellani-type tandem Ortho-selective CH amination transformations.
Abstract: A novel palladium-catalyzed norbornene-mediated three-component reaction for the construction of ortho-alkenyl aromatic tertiary amines has been achieved, which represents a useful extension of the Catellani-type tandem ortho-selective CH amination transformations.
81 citations
TL;DR: A new method to synthesize rigid ladder polymers using efficient palladium catalyzed annulation reactions with low catalyst loading with excellent thermal stability, high carbonization yield, and large intrinsic porosity is reported.
Abstract: We report a new method to synthesize rigid ladder polymers using efficient palladium catalyzed annulation reactions with low catalyst loading (1 mol %). Rigid ladder polymers with benzocyclobutene backbone linkages can be synthesized from copolymerization of readily accessible aryl dibromides and norbornadiene or polymerization of AB type monomers bearing norbornene and aryl bromide or triflate moieties. High molecular weight (10-40 kDa) rigid ladder polymers can be obtained with complete monomer conversions. Diverse monomers also gave different, fixed ladder polymer conformations. The ladder polymers exhibited excellent thermal stability, high carbonization yield, and large intrinsic porosity.
73 citations
TL;DR: It is demonstrated that this can be achieved using a range of functional monomers easily derived from commercially available precursors while their polymerization is carried out in a controlled manner.
Abstract: The potential control over monomer sequence in the ring-opening metathesis polymerization of functional norbornenes is explored based on the difference in reactivity of endo and exo isomers. This kinetic approach allows the rapid consumption of the exo-norbornene and insertion onto the growing poly(norbornene) chain within a narrow region of the overall polymer chain, whilst maintaining a homogeneous backbone. We herein demonstrate that this can be achieved using a range of functional monomers easily derived from commercially available precursors while their polymerization is carried out in a controlled manner.
70 citations
TL;DR: In this paper, the first linear poly(polyoxometalate)s that combine the advantages of polymers and POM clusters were synthesized by linking a Wells-Dawson-type POM with a norbornene derivative.
Abstract: Organic polymers have been found widespread commercial applications due to their easy processing and attractive mechanical properties. Concurrently, inorganic polyoxometalates (POMs), a class of metal–oxygen anionic and nanosized clusters of early transition metals, have a wide range of attractive functions and are used in industrial catalysis. In this communication, we report a new approach to creating the first linear poly(polyoxometalate)s that combine the advantages of polymers and POM clusters. In the experiment, a POM-containing norbornene monomer was first synthesized by linking a Wells-Dawson-type POM with a norbornene derivative. The monomer was polymerized in the presence of a Grubbs catalyst under mild conditions with yields nearly 100% in a living and controllable manner. The resulting poly(polyoxometalate)s have controllable molecular weights and a well-defined hybrid structure of an organic polynorbornene backbone with large pendant groups of the nanosized POM clusters. Thus, they form good ...
67 citations
TL;DR: Ring-opening metathesis polymerization (ROMP) using Grubbs third-generation catalyst directly yielded a norbornene-based polymer bearing robust redox-active radicals without any protection.
Abstract: Ring-opening metathesis polymerization (ROMP) using Grubbs third-generation catalyst directly yielded a norbornene-based polymer bearing robust redox-active radicals without any protection. Successive addition of imidazolium-containing norbornene in a one-pot reaction during ROMP produced pendant radical- and ion-containing block copolymers. The diode-structured thin-film devices fabricated with the obtained block polymers that had morphologies of spheres, lamellae, and inverse spheres exhibited conductive switching (write-once read-many-times, WORM) under a bias voltage, which revealed the dominant effect of the location of radicals and ions in the microphase-segregated domains on memory characteristics.
67 citations
TL;DR: An efficient palladium/norbornene-catalyzed domino reaction of aryl halide, O-acyl hydroxylamine, and aromatic pinacol boronate is reported, selectively affording a series of biaryl tertiary amines in good to high yields with excellent functional group tolerance.
Abstract: Here, we report on an efficient palladium/norbornene-catalyzed domino reaction of aryl halide, O-acyl hydroxylamine (R1R2N-OBz), and aromatic pinacol boronate (R-Bpin), selectively affording a series of biaryl tertiary amines in good to high yields with excellent functional group tolerance. This catalytic reaction provides a new opportunity for the convergent synthesis of biaryl amines from easily accessible starting materials.
66 citations
TL;DR: Insight is provided into mechanistic details for the activation of a diatomic molecule by a prototypical FLP by the reversible formation of a [B]-NO complex intermediate followed by a slower isomerization-ring closure step to the cyclic aminoxyl radical.
Abstract: Described is a kinetics and computational study of the reaction of NO with the intramolecular bridged P/B frustrated Lewis pair (FLP) endo-2-(dimesitylphosphino)-exo-3-bis(pentafluorophenyl)boryl-norbornane to give a persistent FLP-NO aminoxyl radical. This reaction follows a second-order rate law, first-order in [FLP] and first-order in [NO], and is markedly faster in toluene than in dichloromethane. By contrast, the NO oxidation of the phosphine base 2-(dimesitylphosphino)norbornene to the corresponding phosphine oxide follows a third-order rate law, first-order in [phosphine] and second-order in [NO]. Formation of the FLP-NO radical in toluene occurs with a ΔH(‡) of 13 kcal mol(-1), a feature that conflicts with the computation-based conclusion that NO addition to a properly oriented B/P pair should be nearly barrierless. Since the calculations show the B/P pair in the most stable solution structure of this FLP to have an unfavorable orientation for concerted reaction, the observed barrier is rationalized in terms of the reversible formation of a [B]-NO complex intermediate followed by a slower isomerization-ring closure step to the cyclic aminoxyl radical. This combined kinetics/theoretical study for the first time provides insight into mechanistic details for the activation of a diatomic molecule by a prototypical FLP.
63 citations
TL;DR: In this article, a ring-opening metathesis polymerization (ROMP) of functionalised norbornene dicarboximides, side-chain amidation with tri-O-allyl-TRIS, and ring-closing metathetic (RCM) was used to synthesize functional organic nanoparticles.
Abstract: A new approach to prepare functional organic nanoparticles (ONPs) from linear polymers is described. The nanoparticles are obtained by ring-opening metathesis polymerisation (ROMP) of functionalised norbornene dicarboximides, side-chain amidation with tri-O-allyl-TRIS, and ring-closing metathesis (RCM). The synthesis is quite flexible and mild, allowing preparation of organic- and aqueous-soluble particles with narrow molecular weight (MW) distributions that are tunable, ranging from MW ≈ 10 to >100 kD with diameters between ca. 5 and 50 nm. The use of functional monomer(s) and/or chain-transfer agents (CTAs) leads to the fully controlled synthesis of nanoparticles containing single or multiple reactive functional groups. This non-toxic ONP scaffold can be readily used as a protective carrier for a broad range of groups using the appropriate monomers, such as a fluorescein-functionalised monomer that affords fluorescent ONPs with significantly enhanced photostability.
TL;DR: To apply these “click” reactions for site-specific protein labeling, five tyrosine derivatives that contain a norbornene, trans-cyclooctene, or cyclooctyne entity were genetically encoded into proteins in Escherichia coli using an engineered pyrrolysyl-tRNA synthetase-tRNACUAPyl pair.
TL;DR: Inverse electron demand Diels-Alder additions between 1,2,4,5-tetrazines and olefins have recently found widespread application as a novel "click chemistry" scheme and as a mild technique for the modification of materials as discussed by the authors.
TL;DR: Joint palladium/norbornene organometallic catalysis allows for straightforward access to dibenzo[c,e]azepines and DFT modeling sheds light on the complex mechanism that allows the complete diasteroselectivity to be observed.
TL;DR: A straightforward method for the synthesis of highly functionalized vinylarenes through palladium-catalyzed, norbornene-mediated C-H activation/carbene migratory insertion and a Catellani-Lautens reaction that incorporates different types of coupling partners is described.
Abstract: A straightforward method for the synthesis of highly functionalized vinylarenes through palladium-cata- lyzed, norbornene-mediated CH activation/carbene migra- tory insertion is described. Extension to a one-pot procedure is also developed. Furthermore, this method can also be used to generate polysubstituted bicyclic molecules. The re- action proceeds under mild conditions to give the products in satisfactory yields using readily available starting materi- als. This is a Catellani-Lautens reaction that incorporates dif- ferent types of coupling partners. Additionally, this reaction is the first to demonstrate the possibility of combining Pd- catalyzed insertion of diazo compounds and Pd-catalyzed CH activation.
TL;DR: An efficient Pd-catalyzed oxidative cyclization reaction for the synthesis of functionalized indolines by direct C-H activation of acetanilide has been developed and the norbornylpalladium species is supposed to be a key intermediate in this transformation.
TL;DR: In this paper, it was shown that the transformation of norbornene under the investigated conditions suffers from incomplete conversion, but succeeds with gold (I) chloride as the catalyst, which is the same as in this paper.
Abstract: Transformation of norbornene under the investigated conditions suffers from incomplete conversion, but succeeds with gold (I) chloride as the catalyst.
TL;DR: In this paper, a ring-initiated ring-opening metathesis polymerization (SI-ROMP) was employed to prepare polymer-grafted graphene oxide (GO), whose structure and morphology were fully characterized by FTIR, Raman, NMR, XRD, TGA and SEM.
TL;DR: A cobalt-diphosphine catalyst promotes the addition of an arylzinc reagent to a norbornene derivative to afford o-(2-exo-norbornyl)arylzinc species, which can be intercepted by common organic electrophiles under copper or palladium catalysis.
TL;DR: Using thiol addition across norbornene chemistry, a simple synthetic approach to multiblock copolymers that produces either random or alternating architectures, depending on the choice of reactants was demonstrated in this paper.
Abstract: Multiblock copolymers, composed of different combinations and number of blocks, offer appreciable opportunities for new advanced materials. However, exploring this parameter space using traditional block copolymer synthetic techniques, such as living polymerization of sequential blocks, is time-consuming and requires stringent conditions. Using thiol addition across norbornene chemistry, we demonstrate a simple synthetic approach to multiblock copolymers that produces either random or alternating architectures, depending on the choice of reactants. Past reports have highlighted the challenges associated with using thiol–ene chemistry for polymer–polymer conjugation; however, using norbornene as the “ene” yielded multiblock copolymers at least four or five blocks. Preparation of new multiblock copolymers containing two or three block chemistries highlights the versatility of this new approach. These materials were thermally stable and showed microphase separation according to characterization by DSC, SAXS,...
TL;DR: In this article, a green process for the epoxidation of various olefins using polyoxometalate-supported gold nanoparticles as catalysts and using oxygen as the terminal oxidant was reported.
TL;DR: In this article, a series of polynorbornene homopolymers and block copolymers containing side-chain amidoferrocenyl groups and tetraethylene glycol linkers were prepared via living ring-opening metathesis polymerization initiated by Grubbs' third-generation catalyst.
TL;DR: From these results, it is clear that PHOS-FOL-DOX has the potential to act as a smart nanoreservoir with the magnetic field guidance, folate receptor targeting, and finally pH stimulation.
TL;DR: In this paper, a living ROMP of endo-tricyclo[4.2.02,5]deca-3,9-diene (TD) moieties was successfully performed using thermally stable second generation Grubbs and Hoveyda-Grubbs catalysts.
Abstract: Living ROMP of monomers containing endo-tricyclo[4.2.2.02,5]deca-3,9-diene (TD) moieties was successfully performed using thermally stable second generation Grubbs and Hoveyda–Grubbs catalysts. Even slow-initiating catalysts enabled the living polymerization to give polymers with a narrow polydispersity index and controlled molecular weight because the unique structure of the TD monomers resulted in much faster initiation and slower propagation than conventional norbornene monomers. Kinetic analyses confirmed that the ratio of initiation/propagation rate (ki/kp) of the TD monomers was 10 to 200 times larger than that of norbornene derivatives. To demonstrate the living nature of the ROMP, block copolymers were successfully prepared using second generation Hoveyda–Grubbs catalyst for the first time. In addition, three-arm star polymers were prepared by core-first approach using Hoveyda–Grubbs type three-arm initiator, owing to the living ROMP of TD monomers with this stable catalyst. Also, star diblock cop...
TL;DR: Results indicated that introducing a suitable amount of norbornene into the system not only could accelerate the polymerization rate but also could restrain chain transfer reactions to some extent.
Abstract: A series of oxovanadium(V) complexes containing amine pyridine(s) phenolate ligands [ONN] (2a–f) have been synthesized in high yields (68–83%) by reacting VO(OnPr)3 with 1.0 equiv. of the ligands in CH2Cl2. These complexes were characterized by 1H, 13C and 51V NMR spectroscopy and elemental analysis. X-ray structural analysis for 2a, 2c and 2d revealed that these complexes adopt a six-coordinate distorted octahedral geometry around the vanadium center in the solid state. Upon treatment with Et2AlCl and CCl3COOEt, these complexes displayed high catalytic activities for ethylene polymerization even at elevated reaction temperatures, depending on ligand structures. The resulting polymers possessed high molecular weight and unimodal molecular weight distributions, indicative of the formation of a single catalytically active species during the polymerization catalysis. Excitingly, these vanadium(V) complexes could efficiently promote ethylene/norbornene copolymerization. The observed catalytic activity for the copolymerization was higher than that for ethylene homopolymerization. Moreover, the molecular weights of the resulting copolymers increased upon increasing the norbornene feed. These results indicated that introducing a suitable amount of norbornene into the system not only could accelerate the polymerization rate but also could restrain chain transfer reactions to some extent.
TL;DR: A series of (imido)vanadium(V) alkylidene complexes containing an imidazolidin-2-iminato ligand of the type V(CHSiMe3)(NR)(X)(PMe3) (R = 2,6-Me2C6H3 (Ar, 3a), 1-adamantyl (Ad, 3b), C6H5 (3c); X = 1,3-Ar′2(CH2N)2C═N; Ar′ = 2.6-i
Patent•
26 Jun 2014TL;DR: In this article, a substrate with a surface comprising a silane or a non-silane derivative covalently attached to a cycloalkene or a heterocyclo-alkene for direct conjugation with a functionalized molecule of interest is described.
Abstract: Some embodiments described herein relate to a substrate with a surface comprising a silane or a silane derivative covalently attached to optionally substituted cycloalkene or optionally substituted heterocycloalkene for direct conjugation with a functionalized molecule of interest, such as a polymer, a hydrogel, an amino acid, a nucleoside, a nucleotide, a peptide, a polynucleotide, or a protein. In some embodiments, the silane or silane derivative contains optionally substituted norbornene or norbornene derivatives. Method for preparing a functionalized surface and the use in DNA sequencing and other diagnostic applications are also disclosed.
TL;DR: Isospecific and syndioselective ring-opening metathesis polymerization (ROMP) of norbornene (NB) and tetracyclododecene (TCD) have been thoroughly investigated for the first time in this article.
Abstract: Isospecific and syndioselective ring-opening metathesis polymerizations (ROMP) of norbornene (NB) and tetracyclododecene (TCD), as well as their tactic (and atactic) hydrogenated ring-opened polymer products have been thoroughly investigated for the first time. In the case of NB polymerization, cis-isospecific ROMPs of NB were achieved with Mo(═O)(rac-5,5′,6,6′-Me4-3,3′-t-Bu2-biphenolate)2-based catalyst (cis = 100%, isotacticity =100%). Cis-syndioselective ROMPs of NB proceeded in the presence of W(═NPh)Cl4·Et2O- and W(═N-2,6Me2Ph)Cl4·Et2O-based catalysts (cis = 90%, syndiotacticity =90%). Hydrogenated poly(NB)s exhibited high crystallinity irrespective of their stereostructures. The crystalline nature of syndiotactic hydrogenated poly(NB) (syndiotacticity = 90%: Tm = 130–136 °C, ΔH = 60–75 J/g, wc = 0.55–0.70) was close to that of conventional atactic one (meso/racemo = 50/50: Tm = 145–150 °C, ΔH = 65–70 J/g, wc = 0.65). On the contrary, isotactic hydrogenated poly(NB) was characterized by a remarkably ...
TL;DR: In this paper, a series of 3D geometry 9,10-dihydro-9, 10-ethanoanthracene-11,12-diimine methyl palladium chloride complexes were synthesized and characterized.
TL;DR: A palladium-catalyzed three-component reaction of N-tosylhydrazone, norbornene and aryl halide has been demonstrated and provides an efficient and convenient methodology for the double functionalization of norbornenes with good to excellent yields.
Abstract: A palladium-catalyzed three-component reaction of N-tosylhydrazone, norbornene and aryl halide has been demonstrated. In this reaction, an intermolecular Heck-type reaction occurs, which is followed by the alkyl palladium carbene migratory insertion process. This transformation provides an efficient and convenient methodology for the double functionalization of norbornene with good to excellent yields.