Selektive ringöffnende Olefinmetathese mit funktionalisierten monosubstituierten Olefinen

Schneider, Mat­thias; Lucas, Norbert; Velder, Janna; Blechert, Siegfried

doi:10.1002/ange.19971090315

Cited by 27 publications

(13 citation statements)

References 20 publications

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“…Excellent yields (95 %) were obtained, again exceeding those reported in the literature. [26] Heterogeneous RCM experiments: For purposes of comparison, DEDAM, 1,7-octadiene, diallyldiphenylsilane, trans-3-methylpentenoate, and N,N-diallyl-tert-butylcarbamide were used in heterogeneous RCM to benchmark the heterogeneous catalysts 4 and 5. For most of these monomers, both catalyst 5 and 4 displayed high activities in RCM, the latter being the superior system with TONs approaching 1100 ( Table 4, entries 31±35).…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Reactivity of Homogeneous and Heterogeneous Ruthenium‐Based Metathesis Catalysts Containing Electron‐Withdrawing Ligands

Krause

Nuyken

Wurst

et al. 2004

Chemistry A European J

186

166

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The synthesis and heterogenization of new Grubbs-Hoveyda type metathesis catalysts by chlorine exchange is described. Substitution of one or two chlorine ligands with trifluoroacetate and trifluoromethanesulfonate was accomplished by reaction of [RuCl(2)([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] (IMesH(2) = 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene) with the silver salts CF(3)COOAg and CF(3)SO(3)Ag, respectively. The resulting compounds, [Ru(CF(3)SO(3))(2)([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] (1), [RuCl(CF(3)SO(3))([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] (2), and [Ru(CF(3)CO(2))(2)([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] (3) were found to be highly active catalysts for ring-closing metathesis (RCM) at elevated temperature (45 degrees C), exceeding known ruthenium-based catalysts in catalytic activity. Turn-over numbers (TONs) up to 1800 were achieved in RCM. Excellent yields were also achieved in enyne metathesis and ring-opening cross metathesis using norborn-5-ene and 7-oxanorborn-5-ene-derivatives. Even more important, 3 was found to be highly active in RCM at room temperature (20 degrees C), allowing TONs up to 1400. Heterogeneous catalysts were synthesized by immobilizing [RuCl(2)([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] on a perfluoroglutaric acid derivatized polystyrene-divinylbenzene (PS-DVB) support (silver form). The resulting supported catalyst [RuCl(polymer-CH(2)-O- CO-CF(2)-CF(2)-CF(2)-COO)([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] (5) showed significantly reduced activities in RCM (TONs = 380) compared with the heterogeneous analogue of 3. The immobilized catalyst, [Ru(polymer-CH(2)-O-CO-CF(2)-CF(2)-CF(2)-COO)(CF(3)CO(2))([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] (4) was obtained by substitution of both Cl ligands of the parent Grubbs-Hoveyda catalyst by addition of CF(3)COOAg to 5. Compound 4 can be prepared in high loadings (160 mg catalyst g(-1) PS-DVB) and possesses excellent activity in RCM with TONs up to 1100 in stirred-batch RCM experiments. Leaching of ruthenium into the reaction mixture was unprecedentedly low, resulting in a ruthenium content <70 ppb (ng g(-1)) in the final RCM-derived products.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Reactivity of Homogeneous and Heterogeneous Ruthenium‐Based Metathesis Catalysts Containing Electron‐Withdrawing Ligands

Krause

Nuyken

Wurst

et al. 2004

Chemistry A European J

186

166

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“…As shown in Table 6 (entries 1-8), quantitative yields were obtained throughout with 2 mol % of either 1 or 2 at room temperature, which thus rival and in most cases exceed those reported in the literature, including those for H and 5. [53,76] Reactivity in enyne metathesis and cyclopolymerization of 1,6-heptadiynes: The catalytic activity of 1 and 2 in enyne metathesis reactions was tested by investigating the reaction of diethyl dipropargylmalonate (DEDPM) with allyltrimethylsilane. With 10 mol % of 1, only moderate yields (69 %) of the desired compound were obtained (Table 6, entry 9).…”

Section: Resultsmentioning

confidence: 99%

Novel Metathesis Catalysts Based on Ruthenium 1,3‐Dimesityl‐3,4,5,6‐tetrahydropyrimidin‐2‐ylidenes: Synthesis, Structure, Immobilization, and Catalytic Activity

Yang

Mayr

Wurst

et al. 2004

Chemistry A European J

178

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The synthesis of novel ruthenium-based metathesis catalysts containing the saturated 1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene ligand, that is, [RuCl2(NHC)[=CH-2-(2-PrO)-5-NO(2)-C6H3]] (1) and [Ru(CF3COO)2(NHC)[=CH-2-(2-PrO)-5-NO2-C6H3]] (2) (NHC=1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) is described. Both catalysts are highly active in ring-closing metathesis (RCM) and ring-opening cross-metathesis (ROCM). Compound 1 shows moderate activity in enyne metathesis. Compound 2 is not applicable to enyne metathesis since it shows high activity in the cyclopolymerization of diethyl dipropargylmalonate (DEDPM). Poly(DEDPM) prepared by the action of 2 consists of 95% five-membered rings, that is, poly(cyclopent-1-enevinylene)s, and 5 % of six-membered rings, that is, poly(cyclohex-1-ene-3-methylidene)s. The polymerization proceeds in a nonliving manner and results in polyenes with broad polydispersities (1.9< or =PDI< or =2.3). Supported analogues of 2 were prepared by immobilization on hydroxymethyl-Merrifield resin and a monolithic support derived from ring-opening-metathesis polymerization (ROMP). Catalyst loadings of 1 and 2.5%, respectively, were obtained. Both supported versions of 2 showed excellent reactivity. With 0.24-2% of the supported catalysts, yields in RCM and ROCM were in the range of 76-100%. Leaching of ruthenium was low and resulted in Ru contaminations of the products of less than 0.000014% (0.14 ppm).

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“…The ROM of 16 with 14a ran smoothly as reported earlier, using only 0.5 mol% of each immobilized catalyst [30]. However, it was not possible to determine the ratio of the regioisomers despite detailed 2D-NMR experiments.…”

Section: Resultsmentioning

confidence: 93%

The activity of covalently immobilized Grubbs–Hoveyda type catalyst is highly dependent on the nature of the support material

Michalek¹,

Mädge²,

Rühe³

et al. 2006

Journal of Organometallic Chemistry

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Selektive ringöffnende Olefinmetathese mit funktionalisierten monosubstituierten Olefinen

Cited by 27 publications

References 20 publications

Synthesis and Reactivity of Homogeneous and Heterogeneous Ruthenium‐Based Metathesis Catalysts Containing Electron‐Withdrawing Ligands

Synthesis and Reactivity of Homogeneous and Heterogeneous Ruthenium‐Based Metathesis Catalysts Containing Electron‐Withdrawing Ligands

Novel Metathesis Catalysts Based on Ruthenium 1,3‐Dimesityl‐3,4,5,6‐tetrahydropyrimidin‐2‐ylidenes: Synthesis, Structure, Immobilization, and Catalytic Activity

The activity of covalently immobilized Grubbs–Hoveyda type catalyst is highly dependent on the nature of the support material

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