ChemInform Abstract: Hoveyda-Grubbs′ Catalyst Confined in the Nanocages of SBA-1: Enhanced Recyclability for Olefin Metathesis.

ChemInform ◽  
2011 ◽  
Vol 42 (12) ◽  
pp. no-no
Author(s):  
Hengquan Yang ◽  
Zhancheng Ma ◽  
Yuekui Wang ◽  
Yunwei Wang ◽  
Li Fang
Keyword(s):  
Olefin Metathesis ◽  
Grubbs Catalyst

New pseudohalide ligands in Ru-catalyzed olefin metathesis — A robust, air-activated iminopyrrolato catalyst

2005 ◽  
Vol 83 (6-7) ◽  
pp. 748-754 ◽  
Author(s):  
Samantha D Drouin ◽  
Heather M Foucault ◽  
Glenn PA Yap ◽  
Deryn E Fogg
Keyword(s):  
Key Words ◽  
Olefin Metathesis ◽  
High Reactivity ◽  
Ring Closing Metathesis ◽  
Grubbs Catalyst ◽  
X Ray ◽  
X Ray Crystallography

Reaction of the Grubbs catalyst RuCl2(PCy3)2(CHPh) (1) with lithium 2-[(2,6-diisopropylphenyl)imino]pyrrolide·Et2O (LiNN′·Et2O) gives alkylidene complex 5, containing a chelating, σ-bound iminopyrrolato unit. The structure of 5 is confirmed by X-ray crystallography. Treatment of 5 with pyridine generates RuCl(NN′)(py)2(CHPh) (6) via displacement of PCy3. Complex 5 effects ring-closing metathesis in air, displaying high reactivity relative to 6.Key words: ruthenium, alkylidene, metathesis, pyrrolimine, iminopyrrolato.

Hoveyda–Grubbs catalyst confined in the nanocages of SBA-1: enhanced recyclability for olefin metathesis

2010 ◽  
Vol 46 (45) ◽  
pp. 8659 ◽  
Author(s):  
Hengquan Yang ◽  
Zhancheng Ma ◽  
Yuekui Wang ◽  
Yunwei Wang ◽  
Li Fang
Keyword(s):  
Olefin Metathesis ◽  
Grubbs Catalyst

On the ligand properties of the P- versus the N-heterocyclic carbene for a Grubbs catalyst in olefin metathesis

2005 ◽  
Vol 690 (24-25) ◽  
pp. 6079-6088 ◽  
Author(s):  
Wolfgang W. Schoeller ◽  
Daniela Schroeder ◽  
A.B. Rozhenko
Keyword(s):  
Olefin Metathesis ◽  
Grubbs Catalyst

Quest for the ideal olefin metathesis catalyst

2008 ◽  
Vol 80 (1) ◽  
pp. 31-43 ◽  
Author(s):  
Anna Michrowska ◽  
Karol Grela
Keyword(s):  
Oxygen Atom ◽  
Quaternary Ammonium ◽  
Olefin Metathesis ◽  
Amino Group ◽  
Sulfonated Polystyrene ◽  
Grubbs Catalyst ◽  
Metathesis Catalyst ◽  
Metathesis Catalysts ◽  
Novel Strategy ◽  
The Ideal

Attempts were made to create a catalyst that approaches Gladysz's vision of an "ideal catalyst". Modifications of the Hoveyda-Grubbs catalyst were carried out with the aim to increase its activity and broaden the scope of its applicability to challenging metathesis reactions. This was done by introduction of an electron-withdrawing substituent on the isopropoxybenzylidene group in order to diminish the donor properties of the oxygen atom. The resulting stable and easily accessible nitro-substituted Hoveyda-Grubbs catalyst has found a number of successful applications in various research and industrial laboratories. Also, a new concept for noncovalent immobilization of a ruthenium olefin metathesis catalyst is presented. The 2-isopropoxybenzylidene ligand of Hoveyda-Grubbs carbene is further modified by an additional amino group, and immobilization is achieved by treatment with sulfonated polystyrene, forming the corresponding ammonium salt. In this novel strategy for the immobilization of ruthenium-based metathesis catalysts, the amino group plays a dual role, being first an active anchor for immobilization and secondly, after protonation, activating the catalysts by electron-donating to -withdrawing switch. The same concept has been used in the preparation of a quaternary ammonium catalyst for aqueous olefin metathesis.

A facile new procedure for the deprotection of allyl ethers under mild conditions

2000 ◽  
Vol 78 (6) ◽  
pp. 838-845 ◽  
Author(s):  
Yun-Jin Hu ◽  
Romyr Dominique ◽  
Sanjoy Kumar Das ◽  
René Roy
Keyword(s):  
Key Words ◽  
Catalytic System ◽  
Olefin Metathesis ◽  
Allyl Ether ◽  
Metathesis Reaction ◽  
Grubbs Catalyst ◽  
Allyl Ethers ◽  
Mild Conditions ◽  
Cross Metathesis ◽  
Allylic Ethers

A novel isomerization of O-allyl glycosides into prop-1-enyl glycosides was observed instead of cross-metathesis during an olefin metathesis reaction using Grubbs' ruthenium benzylidene catalyst (Cy3P)2RuCl2=CHPh (1), N-allyltritylamine, and N,N-diisopropylethylamine as necessary auxiliary reagents. In the search for a better catalytic system, it has been found that dichlorotris(triphenylphosphine)ruthenium(II), [(C6H5)3P]3RuCl2, (2) was much more efficient for the isomerization of allylic ethers. The labile prop-1-enyl group was easily hydrolyzed using HgCl2-HgO and the hemiacetals (25-32) were isolated in excellent yields (ca. 90%).Key words: allyl ether, carbohydrate, Grubbs' catalyst, isomerization, metathesis, deprotection.

scholarly journals Ethyl Linoleate Derivatives from Olefin Metathesis as a Function of the Starting Complex and Reactivity Conditions

2017 ◽  
Author(s):  
Cristina Vidal da S. Neta ◽  
Yan F. da Silva ◽  
Valdemiro P. Carvalho Jr ◽  
Benedito Dos S. Lima-Neto ◽  
José Luiz S. Sá
Keyword(s):  
Olefin Metathesis ◽  
First Generation ◽  
Relative Proportion ◽  
Ethyl Linoleate ◽  
Compound K ◽  
Reaction Conditions ◽  
Grubbs Catalyst ◽  
Co Catalyst ◽  
Relative Percentage ◽  
Catalyst Type

Olefin metathesis of ethyl linoleate (EL) was investigated under different conditions of substrate amount, temperature, and catalyst. Second-generation Grubbs catalyst (G2) was used in experiments at 20 and 50 ºC for 24 and 48h, whereas first-generation Grubbs catalyst (G1) and [RuCl2(PPh3)2perhydroazepine] (LN) were used in experiments at 50 ºC for 24h, with the latter also being investigated in the presence or absence of SnCl2 as co-catalyst. Catalytic products were analyzed for GC-MS and discussed in terms of relative percent of the metathesis products. With G2 as catalyst, GC-MS chromatograms were similar in all the amounts of EL investigated at 50 ºC for 24h, except for ethyl hexadec-9-enoate (compound K), which was obtained with different percentage as a function of EL amount (55% for 2 and 5 mL and 65% for 8 mL). An α,ω-dicarboxylic acid with m/z = 444.00 (compound L) was produced from the experiments at 50 ºC for 24h with similar percentage as a function of EL amount. However, the relative percentage of L changed with the increase of EL volume in the experiments at 20 ºC (ca. 18, 27, and 28%, with 2, 5, and 8 mL of EL, respectively). The olefin metathesis of EL conducted by G1 reached lower selectivity than that conducted by G2 for 24h at 50 ºC. Several intense peaks reached with G1 were similar to those obtained with G2, in addition to new peaks of medium intensity. Compound L showed higher m/z, similar to that presented with G2, but with lower relative proportion in the mixture. LN was inert for olefin metathesis of EL; however, it was activated in the presence of SnCl2 at 50 ºC for 24h. Different compounds and selectivity as a function of the catalyst type and reaction conditions were obtained.

Application of Amine-based Ru Compounds in the Olefin Metathesis of Methyl Eugenol: A Comparison with Grubbs Catalysts

2020 ◽  
Vol 17 (8) ◽  
pp. 596-602
Author(s):  
Denise A. Sousa ◽  
Paulo S. Meneses ◽  
Patrik D.S. Gois ◽  
Eliada A. Silva ◽  
Valdemiro P.C. Junior ◽  
...  
Keyword(s):  
Olefin Metathesis ◽  
Methyl Eugenol ◽  
Grubbs Catalyst ◽  
Catalytic Activities ◽  
2Nd Generation ◽  
Grubbs Catalysts ◽  
Ru Complexes

Methyl eugenol olefin metathesis was conducted with non-carbene Ru-complexes ([RuCl2(PPh3)2amine]) in the absence and presence of SnCl2 or CuCl2 as additives and their catalytic activities were compared with that of a commercial Grubbs catalyst 2nd Generation (G2).

scholarly journals The Influence of Various N-Heterocyclic Carbene Ligands on Activity of Nitro-Activated Olefin Metathesis Catalysts

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2282 ◽  
Author(s):  
Michał Pieczykolan ◽  
Justyna Czaban-Jóźwiak ◽  
Maura Malinska ◽  
Krzysztof Woźniak ◽  
Reto Dorta ◽  
...  
Keyword(s):  
High Activity ◽  
Olefin Metathesis ◽  
Double Bonds ◽  
Carbene Ligands ◽  
Grubbs Catalyst ◽  
Metathesis Reactions ◽  
Metathesis Catalysts

A set of nitro-activated ruthenium-based Hoveyda-Grubbs type olefin metathesis catalysts bearing sterically modified N-hetero-cyclic carbene (NHC) ligands have been obtained, characterised and studied in a set of model metathesis reactions. It was found that catalysts bearing standard SIMes and SIPr ligands (4a and 4b) gave the best results in metathesis of substrates with more accessible C–C double bonds. At the same time, catalysts bearing engineered naphthyl-substituted NHC ligands (4d–e) exhibited high activity towards formation of tetrasubstituted C–C double bonds, the reaction which was traditionally Achilles’ heel of the nitro-activated Hoveyda–Grubbs catalyst.

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