Activation of Cycloolefin Metathesis by Ultrasonic Irradiation

Drăguţan, Ileana; Drăguţan, Valerian; Filip, Petru; Demonceau, Albert

doi:10.1007/978-90-481-3433-5_20

Cited by 6 publications

(9 citation statements)

References 37 publications

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“…16,17,18 The organic reactants were inexpensive, and the metals were used in catalytic amounts. Purification of the triazole product from the click reaction required only a simple filtration.…”

Section: Discussionmentioning

confidence: 99%

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“Click” and Olefin Metathesis Chemistry in Water at Room Temperature Enabled by Biodegradable Micelles

et al. 2013

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The two laboratory reactions focus on teaching several concepts associated with green chemistry. Each uses a commercial, nontoxic, and biodegradable surfactant, TPGS-750-M, to promote organic reactions within the lipophilic cores of nanoscale micelles in water. These experiments are based on work by K. Barry Sharpless (an azide–alkyne “click” reaction) and Robert Grubbs (an olefin cross-metathesis reaction); both are suitable for an undergraduate organic laboratory. The copper-catalyzed azide–alkyne [3+2] cycloaddition of benzyl azide and 4-tolylacetylene is very rapid: the triazole product is readily isolated by filtration and is characterized by thin-layer chromatography and melting point analysis. The ruthenium-catalyzed olefin cross-metathesis reaction of benzyl acrylate with 1-hexene is readily monitored by thin-layer chromatography and gas chromatography. The metathesis experiment comparatively evaluates the efficacy of a TPGS-750-M/water medium relative to a traditional reaction performed in dichloromethane (a common solvent used for olefin metathesis).

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Section: Discussionmentioning

confidence: 99%

“…18 The olefin metathesis experiment also provided the opportunity to discuss the 2005 Nobel Prizes in Chemistry; 12 particular emphasis was given to reaction mechanism and scope. For example, the 1971 mechanism proposed by Hérisson and Chauvin 22 was used to rationalize the formation of the cross product.…”

Section: Discussionmentioning

confidence: 99%

“Click” and Olefin Metathesis Chemistry in Water at Room Temperature Enabled by Biodegradable Micelles

et al. 2013

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“…1 Olefin metathesis has also garnered recent interest due to its potential in green chemistry applications. 2 In particular, the commercially-available ruthenium olefin metathesis catalysts 1-4 have been extensively used in organic and polymer chemistry due to their robustness, high activity, and functional group tolerance (Figure 1). 1a,3 …”

Section: Introductionmentioning

confidence: 99%

Characterization and Dynamics of Substituted Ruthenacyclobutanes Relevant to the Olefin Cross-Metathesis Reaction

et al. 2011

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The reaction of the phosphonium alkylidene [(H2IMes)RuCl2=CHP(Cy)3)]+ BF4– with propene, 1-butene, and 1-hexene at –45 °C affords various substituted, metathesis-active ruthenacycles. These metallacycles were found to equilibrate over extended reaction times in response to decreases in ethylene concentrations, which favored increased populations of α-monosubstituted and α,α’-disubstituted (both cis and trans) ruthenacycles. On an NMR timescale, rapid chemical exchange was found to preferentially occur between the β-hydrogens of the cis and trans stereoisomers prior to olefin exchange. Exchange on an NMR timescale was also observed between the α- and β-methylene groups of the monosubstituted ruthenacycle (H2IMes)Cl2Ru(CHRCH2CH2) (R = CH3, CH2CH3, (CH2)3CH3). EXSY NMR experiments at –87 °C were used to determine the activation energies for both of these exchange processes. In addition, new methods have been developed for the direct preparation of metathesis-active ruthenacyclobutanes via the protonolysis of dichloro(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)(benzylidene) bis(pyridine)ruthenium(II) and its 3-bromopyridine analog. Using either trifluoroacetic acid or silica-bound toluenesulfonic acid as the proton source, the ethylene-derived ruthenacyclobutane (H2IMes)Cl2Ru(CH2CH2CH2) was observed in up to 98% yield via NMR at –40 °C. On the basis of these studies, mechanisms accounting for the positional and stereochemical exchange within ruthenacyclobutanes are proposed, as well as the implications of these dynamics towards olefin metathesis catalyst and reaction design are described.

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“…With introduction of the new generations of highly active and chemoselective Ru metathesis catalysts endowed with high tolerance towards many functionalities and good stability in the presence of air, moisture and various solvents, including water-containing systems [231,232,233,234,235,236,237,238,239], the diversification of metathesis reactions experienced a strong impetus [240,241,242,243,244,245]. Among metathesis reactions, cross-metathesis (CM) [246,247,248,249] and ring-closing metathesis (RCM) [250,251,252,253,254] have become the most encountered strategies for the synthesis of linear and branched, or carbocyclic and heterocyclic compounds.…”

Section: Ruthenium Complexes In Catalysismentioning

confidence: 99%

“…Synthesis, involving enyne metathesis, of biologically and medicinally significant molecules like (+)-anatoxin-A, (+)-anthramycin, artemisinin, transtaganolide D, allo-colchicine, (−)-galanthamine, (−)-longithorone A, (+)-ochromycinone, (+)-rubiginone B2, and (−)-stemoamide have become attractive when starting from adequate substrates [274]. It should be emphasized that cross-metathesis allowed diversification of synthetic strategies by employing substrates that are tolerated by the new generations of Ru complexes [231,236,237,238,239,243,244,246,247,248,249]. A remarkably creative work encompasses the total synthesis of (−)-amphidinolide K and V applying an ingenious combination of Mo with Ru metathesis catalytic systems [275].…”

Section: Ruthenium Complexes In Catalysismentioning

confidence: 99%

Editorial of Special Issue Ruthenium Complex: The Expanding Chemistry of the Ruthenium Complexes

Drăguţan

Demonceau

2015

Molecules

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Activation of Cycloolefin Metathesis by Ultrasonic Irradiation

Cited by 6 publications

References 37 publications

“Click” and Olefin Metathesis Chemistry in Water at Room Temperature Enabled by Biodegradable Micelles

“Click” and Olefin Metathesis Chemistry in Water at Room Temperature Enabled by Biodegradable Micelles

Characterization and Dynamics of Substituted Ruthenacyclobutanes Relevant to the Olefin Cross-Metathesis Reaction

Editorial of Special Issue Ruthenium Complex: The Expanding Chemistry of the Ruthenium Complexes

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