Ring‐Closure Metathesis in Supercritical Carbon Dioxide as Sole Solvent with Use of Covalently Immobilized Ruthenium Catalysts

Michalek, Florian; Mädge, Daniel; Rühe, Jürgen; Bannwarth, Willi

doi:10.1002/ejoc.200500738

Cited by 46 publications

(16 citation statements)

References 50 publications

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“…[99] Whereas, excellent recycling was observed with the unsupported catalysts, the immobilized versions yielded more modest performances. Nevertheless, interestingly low levels of Ru contamination were observed with this combination of supported catalysts and scCO 2 (%20 ppm vs 100 ppm with both generations of Grubbs catalysts in sCO 2 ).…”

Section: Metathesis In Supercritical Carbon Dioxidementioning

confidence: 95%

Sustainable Concepts in Olefin Metathesis

et al. 2007

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Ruthenium-catalyzed olefin metathesis reactions represent an attractive and powerful transformation for the formation of new carbon-carbon double bonds. This area is now quite familiar to most chemists as numerous catalysts are available that enable a plethora of olefin metathesis reactions. Nevertheless, with the exception of uses in polymerization reactions, only a limited number of industrial processes use olefin metathesis. This is mainly due to difficulties associated with removing ruthenium from the final products. In this context, a number of studies have been carried out to develop procedures for the removal of the catalyst or the products of catalyst decomposition, however, none are universally attractive so far. This situation has resulted in tremendous activity in the area dealing with supported or tagged versions of homogeneous catalysts. This Review summarizes the numerous studies focused on developing cleaner ruthenium-catalyzed metathesis processes.

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Section: Metathesis In Supercritical Carbon Dioxidementioning

confidence: 95%

Sustainable Concepts in Olefin Metathesis

et al. 2007

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“…Mo{N[2,6-Me 2 -4(6-ClC 6 H 12 )]C 6 H 2 } 2 Cl 2 A C H T U N G T R E N N U N G (DME) (12) A C H T U N G T R E N N U N G (NH 4 ) 6 Mo 7 O 24 ·4 H 2 O (0.713 g, 0.577 mmol) was suspended in DME (60 mL) at room temperature. 2,6-Lutidine (1.88 mL, 16.2 mmol) and trimethylsilyl chloride (5.37 mL, 42.4 mmol) were added and the solution was stirred for 10 min.…”

Section: Mo{n[26-me 2 -4(6-brc 6 H 12 )]C 6 H 2 } 2 CL 2 a C H T U Nmentioning

confidence: 99%

“…In metathesis reactions, the latter is often restricted by the instability of intermediate transition metal methylidenes. While a comparably large number of supported ruthenium-based Grubbs-and Grubbs-Hoveyda-type metathesis catalysts are already available, [10][11][12] there exists still an only very limited number of supported Schrock-type catalysts. [6] In this context, surface-located transition metal carbenes have been reported to possess metathesis activity.…”

Section: Introductionmentioning

confidence: 99%

Polymer‐Supported Chiral Schrock Catalysts Immobilized via the Arylimido Ligand

et al. 2006

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The immobilization of both chiral and non-chiral versions of the Schrock catalyst via the arylimido ligand was accomplished for the first time. For this purpose, four different 4-(6-halogenohexyl)-2,6-R 2 -anilines, i.e., {4-[6-X-(CH 2 ) 6 ]-2,6-R 2 -C 6 H 2 -NH 2 } (7: R= Me, X = Br; 8: R= Me, X = Cl, 9: R= 2-Pr, X = Cl, 10: R= 2-Pr, X = Br) were prepared and used for the synthesis of the corresponding MobisA C H T U N G T R E N N U N G (imido)dichloro complexes Mo{N-2,6-R 2 -4-[6-X-(CH 2 ) 6 ]-C 6 H 2 } 2 Cl 2 ·DME (11: R= Me, X = Br; 12: R = Me, X = Cl; 13: R= 2-Pr, X = Cl; 14: R= 2-Pr, X = Br). Compounds 11-14 were transformed into the corresponding Mo-bisA C H T U N G T R E N N U N G (imido)dialkyl complexes Mo{N-2,6-R 2 -4-[6-X-(CH 2 ) 6 ]-C 6 H 2 } 2 (CH 2 CMe 2 Ph) 2 (15: R= Me, X = Br; 16: R= Me, X = Cl, 17: R= 2-Pr, X = Cl; 18: R= 2-Pr, X = Br). These were used for the synthesis of the Mo-imidoalkylidene triflates·DME (19: R= Me, X = Br; 20: R= 2-Pr, X = Br, 21: R= 2-Pr, X = Cl). Compounds 19--21 were used in the synthesis of the Schrock type catalysts H T U N G T R E N N U N G (CHCMe 2 Ph)[OC-A C H T U N G T R E N N U N G (CH 3 )A C H T U N G T R E N N U N G (CF 3 ) 2 ] (23), Mo{N-2,6-Me 2 -4-[6-Br-(CH 2 ) 6 ]-C 6 H 2 }A C H T U N G T R E N N U N G (CHCMe 2 Ph)[(R)-BIPHEN] (24) and MoA C H T U N G T R E N N U N G {N-2,6-A C H T U N G T R E N N U N G (2-Pr) 2 -4-[6-Br-(CH 2 ) 6 ]-C 6 H 2 }A C H T U N G T R E N N U N G (CHCMe 2 Ph)[(R)-BIPHEN] (25). Compounds 22, 24and 25 were immobilized on Ag-perfluoroalkylsulfonate-modified PS-and PS-DVB materials to yield the corresponding immobilized catalysts Mo{N-2,6-Me 2 -4-28). These were used in a series of ring-closing metathesis (RCM), ringopening cross metathesis, asymmetric RCM and desymmetrization reactions. The use of 27 and 28 resulted in values for enantiomeric excess (ee) virtually identical to those obtained with the corresponding homogeneous chiral catalysts.

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“…Other C-C coupling reactions performed in supercritical CO 2 were, for example, the Heck reaction with Pd/C [126], a ring closure-metathesis reaction with covalent immobilized Ru complexes [127], and hydroformylation with immobilized metal-organic catalysts [128][129][130][131][132][133][134][135][136][137][138][139][140][141][142].…”

Section: C-c Bondsmentioning

confidence: 99%

Heterogeneous Catalysis in Supercritical Media: 1. Carbon Dioxide

Kruse

Vogel

2007

Chem Eng & Technol

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Dedicated to Prof. Dr.-Ing. Jens Weitkamp on the occasion of his 65th birthdayOver the past few years, supercritical fluids have received considerable interest as reaction media. Supercritical fluids combine properties of gases and liquids. Densities are lower than in the liquid phase, but significantly higher than in the gas phase. This makes supercritical fluids excellent solvents for a variety of substances. The good dissolution capacity exists only in or near the supercritical range. Reaction products can be separated, for instance, simply by decreasing temperature and pressure. This may be used to intensify the process as complex separation processes, like distillation, are avoided.

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Ring‐Closure Metathesis in Supercritical Carbon Dioxide as Sole Solvent with Use of Covalently Immobilized Ruthenium Catalysts

Cited by 46 publications

References 50 publications

Sustainable Concepts in Olefin Metathesis

Sustainable Concepts in Olefin Metathesis

Polymer‐Supported Chiral Schrock Catalysts Immobilized via the Arylimido Ligand

Heterogeneous Catalysis in Supercritical Media: 1. Carbon Dioxide

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