Synthesis, characterization, and catalytic activity of a ruthenium carbene complex coordinated with bidentate 2-pyridine-carboxylato ligands

Hahn, F. Ekkehardt; Paas, Martin; Fröhlich, Roland

doi:10.1016/j.jorganchem.2005.07.060

Cited by 27 publications

(16 citation statements)

References 33 publications

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“…39 They concluded a remarkably low room temperature activity of these precatalysts but illustrated the use of Brønsted acids, such as HCl or H 2 SO 4 , to activate the catalyst. Zhang et al elaborated the possibility of a bidentate phosphino-carboxylato ligand, envisioning the dissociation of the phosphine from the ruthenium at elevated temperatures to initiate olefin metathesis while the carboxylate group remains coordinated to the ruthenium center (Scheme 12, 27; Table 2, entries [35][36][37][38]. 40 While these complexes are straightforwardly obtained from reaction of a second generation Grubbs type complex with the corresponding sodium phosphine-carboxylates, they exhibit medium to high activity for the RCM of diethyl diallylmalonate at 40 1C and 70 1C.…”

Section: Catalysts Bearing Dangling Ligandsmentioning

confidence: 99%

Latent olefin metathesis catalysts

et al. 2009

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Olefin metathesis is a versatile synthetic tool for the redistribution of alkylidene fragments at carbon-carbon double bonds. This field, and more specifically the development of task-specific, latent catalysts, attracts emerging industrial and academic interest. This tutorial review aims to provide the reader with a concise overview of early breakthroughs and recent key developments in the endeavor to develop latent olefin metathesis catalysts, and to illustrate their use by prominent examples from the literature.

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Section: Catalysts Bearing Dangling Ligandsmentioning

confidence: 99%

Latent olefin metathesis catalysts

et al. 2009

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“…[10] This catalyst showed excellent stability towards air and moisture and could be recycled several times. Various other efforts have been directed towards the modification of the Grubbs catalysts, such as the introduction of bidentate Schiff base ligands, [11,12] substituted acetic acid groups, [13][14][15][16] different alkoxides, [17,18] halides, [19] pyridines, [18,20,21] phenoxides, [22,23] less electron-donating phosphines, [24] several pyridinecarboxylates [25] and indenylidene ligand substituting benzylidene. [26,27] Recently, our group has reported new robust ruthenium-indenylidene complexes bearing a saturated N-heterocyclic carbene ligand, showing both high activity and increased stability with an excellent application profile.…”

Section: Introductionmentioning

confidence: 99%

New Indenylidene‐Schiff Base‐Ruthenium Complexes for Cross‐Metathesis and Ring‐Closing Metathesis

Vila¹,

Monsaert²,

Drozdzak³

et al. 2009

Adv Synth Catal

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We here report on the stability and catalytic activity of new indenylidene-Schiff base-ruthenium complexes 3a-f through representative cross-metathesis (CM) and ring-closing metathesis (RCM) reactions. Excellent activity of the new complexes was found for the two selected RCM reactions; prominent conversion was obtained compared to the commercial Hoveyda-Grubbs catalyst 2. Moreover, excellent results were obtained for a standard CM reaction. Higher conversions were achieved with one of the indenylidene catalysts compared with HoveydaGrubbs catalyst. Unexpectedly, an isomerization reaction was observed during the CM reaction of allylbenzene. To the best of our knowledge, isomerization reactions in this model CM reaction in closed systems have never been described using first generation catalysts, including the Hoveyda-Grubbs catalyst. The first model CM reactions as well as the RCM reactions have been monitored using 1 H NMR. The course of the CM reaction of 3-phenylprop-1-ene (8) and cis-1,4-diacetoxybut-2-ene (9) was monitored by GC. The isomerization reaction was studied by means of GC-mass spectrometry and in situ IR spectroscopy. All catalysts were structurally characterized by means of 1 H, 13 C, and 31 P NMR spectroscopy.

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“…[29,30] This specialized catalyst is also active in methanol-water mixtures, with 10 mol% of 7c achieving the highest conversion of N,N-diallylamine hydrochloride (10d) to RCM product 11d yet reported in an aqueous environment. [9,11,[30][31][32] Moreover, 7c accomplishes this transformation cleanly. For comparison, Grubbs and coworkers reported 67% ring-closing of 10d along with 28% conversion to cycloisomer 12d using 5 mol% of complex 4b in water at room temperature over 36 h. [9] With a variety of nonpolar dienes 7c also achieves good to excellent conversions to five-, six-, and seven-membered rings in methanol-water mixtures.…”

Section: Ring-closing Metathesis Activity Of 7a-cmentioning

confidence: 99%

Salicylaldimine Ruthenium Alkylidene Complexes: Metathesis Catalysts Tuned for Protic Solvents

2007

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Tuning the electronic and steric environment of olefin metathesis catalysts with specialized ligands can adapt them to broader applications, including metathesis in aqueous solvents. Bidentate salicylaldimine ligands are known to stabilize ruthenium alkylidene complexes, as well as allow ring-closing metathesis in protic media. Here, we report the synthesis and characterization of exceptionally robust olefin metathesis catalysts bearing both bidentate salicylaldimine and N-heterocyclic carbene ligands, including a trimethylammoniumfunctionalized complex adapted for polar solvents. NMR spectroscopy and X-ray crystallographic analysis confirm the structures of the complexes. Although the N-heterocyclic carbenesalicylaldimine ligand combination limits the activity of these catalysts in nonpolar solvents, this pairing enables efficient ring-closing metathesis of both dienes and enynes in methanol and methanol-water mixtures under air.

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Synthesis, characterization, and catalytic activity of a ruthenium carbene complex coordinated with bidentate 2-pyridine-carboxylato ligands

Cited by 27 publications

References 33 publications

Latent olefin metathesis catalysts

Latent olefin metathesis catalysts

New Indenylidene‐Schiff Base‐Ruthenium Complexes for Cross‐Metathesis and Ring‐Closing Metathesis

Salicylaldimine Ruthenium Alkylidene Complexes: Metathesis Catalysts Tuned for Protic Solvents

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