Olefin isomerization promoted by olefin metathesis catalysts

Lehman, Stephen E.; Schwendeman, John E.; O’Donnell, Patrick M.; Wagener, Kenneth B.

doi:10.1016/s0020-1693(02)01307-5

Cited by 139 publications

(121 citation statements)

References 44 publications

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“…Grubbs first generation catalyst was used based on previous work in our group showing that this catalyst does not cause olefin isomerization, which is a critical point in obtaining a precisely defined primary structure. [24] The polymerization was conducted at 35-40 8C under vacuum with stirring for 5 days. The reaction was then stopped and 5 mL of toluene were added to dissolve the polymer with stirring.…”

Section: Methodsmentioning

confidence: 99%

Precision Ethylene/Vinyl Bromide Polymers

et al. 2007

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Here we report the synthesis of precision ethylene/vinyl bromide (EV/B) polymers via metathesis chemistry followed by exhaustive hydrogenation. The polymer primary structures are supported by 1 H NMR, 13C NMR, elemental analysis, TGA, and IR. Thermal analysis by DSC shows that a linear trend exists between increasing bromine content and decreasing melting temperature as bromine is incorporated (as a defect) in the crystalline lattice. In reference to the defect-free chain, a change in phase structure causes a dramatic decrease in the observed heat of fusion and a smooth decrease within the Br series. This study describes the first family of precise EV/B polymers reported in the literature.

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Section: Methodsmentioning

confidence: 99%

Precision Ethylene/Vinyl Bromide Polymers

et al. 2007

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“…The lithium salts of pyridinyls were then allowed to react with benzophenone, 2-chlorobenzophenone, 4-chlorobenzophenone or 4-methoxybenzophenone after raising the temperature to −20 °C for 2 h, which, in the end, was raised to room temperature, followed by careful hydrolysis. This resulted in 48% 1,1-diphenyl-1-(2′-pyridinyl)-methanol (5), 89% 1-(2′-chlorophenyl)-1-phenyl-1-(2′-pyridinyl)-methanol (6), 80% 1-(4′-chlorophenyl)-1-phenyl-1-(2′-pyridinyl)-methanol (7) and 70% 1-(4′-methoxyphenyl)-1-phenyl-1-(2′-pyridinyl)-methanol (8). The structures of the alcohols were elucidated using IR (Infrared spectrometry), NMR (Nuclear Magnetic Resonance spectrometry) and MS (Mass Spectrometry) (see Section 3).…”

Section: Synthesis Of Pyridinyl Alcoholsmentioning

confidence: 99%

“…These precatalysts however showed activity at room temperature in alkene metathesis reactions [2,8,9]. Although they perform excellent at room temperature, they have a relatively short catalytic lifetime.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Application of Novel Ruthenium Catalysts for High Temperature Alkene Metathesis

et al. 2017

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Four pyridinyl alcohols and the corresponding hemilabile pyridinyl alcoholato ruthenium carbene complexes of the Grubbs second generation-type RuCl(H 2 IMes)(OˆN)(=CHPh), where,1-phenyl methanolato and 1-(2 -pyridinyl)-1-(2 -methoxyphenyl),1-phenyl methanolato, are synthesized in very good yields. At high temperatures, the precatalysts showed high stability, selectivity and activity in 1-octene metathesis compared to the Grubbs first and second generation precatalysts. The 2-/4-chloro-and 4-methoxy-substituted pyridinyl alcoholato ligand-containing ruthenium precatalysts showed high performance in the 1-octene metathesis reaction in the range 80-110 • C. The hemilabile 4-methoxy-substituted pyridinyl alcoholato ligand improved the catalyst stability, activity and selectivity for 1-octene metathesis significantly at 110 • C.

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“…A recent report by Grubbs has identified the structure of a thermal decomposition product, a bridged Ru 2 -carbide hydride, that is also an active isomerization catalysts [96]. In some instances, the more active N-heterocyclic carbene Ru complexes, such as 2, show a greater propensity for isomerization activity than the original P(Cy) 3 system 1 [97]. The Mo-based catalysts of Schrock, such as 3, are only rarely reported to be involved in this type of reactivity [98,99].…”

Section: Olefin Isomerizationmentioning

confidence: 99%

Ring closing metathesis employing organometallic substrates and the templated synthesis of macrocycles

Chase

Lutz

Spek

et al. 2006

Journal of Molecular Catalysis A: Chemical

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Templation is a well-known strategy for the selective generation of complex products. Ring-closing metathesis, catalyzed by well-characterized Ru and Mo catalysts, is a powerful method for C C bond formation and has certainly developed into one of the most important modern reactions in organic synthesis and in polymer chemistry. Despite the extensive research on this reaction, the use of organometallic containing substrates is not well-studied. Here, we give a detailed account of our ongoing efforts to employ ring-closing metathesis with bis(␣-olefin) substituted pyridines in the presence of trimeric metallopincer templates for the selective synthesis of macroheterocycles with ring sizes up to 81 atoms.

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Olefin isomerization promoted by olefin metathesis catalysts

Cited by 139 publications

References 44 publications

Precision Ethylene/Vinyl Bromide Polymers

Precision Ethylene/Vinyl Bromide Polymers

Synthesis and Application of Novel Ruthenium Catalysts for High Temperature Alkene Metathesis

Ring closing metathesis employing organometallic substrates and the templated synthesis of macrocycles

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