Synthesis and Application of Novel Ruthenium Catalysts for High Temperature Alkene Metathesis

Tole, Tegene Tesfaye; Toit, Jean I. du; Sittert, Cornelia Gertina Catharina Elizabeth van; Jordaan, Johannes H.; Vosloo, Hermanus C.M.

doi:10.3390/catal7010022

Cited by 7 publications

(10 citation statements)

References 49 publications

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“…The combination of the NHC ligand and the chelating ability of the pyridinyl alcoholato ligands are responsible for the stability and activity of the catalyst at high temperatures. Incorporating other electron-donating (OMe) and electron-withdrawing (Cl) at the 2- or 4-position on one of the α-phenyl groups of 16d showed improved catalytic performance for 1-octene metathesis at temperatures ranging from 80–110 °C [ 32 ]. The 4-methoxy-substituted complex outperformed the rest at 110 °C (96% conversion with 95% selectivity towards the major products 7-tetradecene and ethene).…”

Section: Synthesis and Application Of Transition Metal Complexes Omentioning

confidence: 99%

“…The 4-methoxy-substituted complex outperformed the rest at 110 °C (96% conversion with 95% selectivity towards the major products 7-tetradecene and ethene). A modelling study suggested that the improved catalytic performance can be attributed to steric repulsion between the substituted phenyl group and the NHC ligand resulting in strengthening the Ru-N bond [ 32 ]. Slugovc and Wattel [ 33 ] patented a number of 8-quinolinolate Gr2 derivatives for use in ROMP reactions.…”

Section: Synthesis and Application Of Transition Metal Complexes Omentioning

confidence: 99%

“…The chelation ability of the pyridinyl alcohol nitrogen combined with the stable NHC ligand is responsible for the increment in the activity and stability of the catalysts. The investigations of Vosloo and co-workers [ 26 , 27 , 29 , 30 , 31 , 32 ] were focused on the steric and electronic effects of the groups on the carbon atom to which the alcohol function was attached in the pyridinyl alcohol. Even though the electronic effect of the substituents did not show significant influence on the catalyst activity, the steric effect is clearly seen on the 16d precatalyst stability.…”

Section: Synthesis and Application Of Transition Metal Complexes Omentioning

confidence: 99%

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Synthesis and Application of the Transition Metal Complexes of α-Pyridinyl Alcohols, α-Bipyridinyl Alcohols, α,α’-Pyridinyl Diols and α,α’-Bipyridinyl Diols in Homogeneous Catalysis

2018

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The paper presents a comprehensive survey on the synthetic procedures of transition metal complexes of α-pyridinyl alcoholato, α-bipyridinyl alcoholato, α,α’-pyridinyl dialcoholato and α,α’-bipyridinyl dialcoholato ligands and their coordination chemistry. Greater emphasis is, however, given to the catalytic activity of the complexes in homogeneous and asymmetric chemical reactions. The multidentate character of the pyridinyl alcohols and/or bipyridinyl diols is of great importance in the complexation with a large number and type of transition metals. The transition metal complexes of pyridinyl alcoholato or bipyridinyl dialcoholato ligands in most cases, and a few pyridinyl alcohols alone, were used as catalysts in homogeneous and chemical asymmetric reactions. In most of the homogeneously catalysed enantioselective chemical reactions, limited numbers and types of pyridinyl alcohols and or bipyridinyl diols were used in the preparation of chiral catalysts that led to a few investigations on the catalytic importance of the pyridinyl alcohols.

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Section: Synthesis and Application Of Transition Metal Complexes Omentioning

confidence: 99%

Section: Synthesis and Application Of Transition Metal Complexes Omentioning

confidence: 99%

Section: Synthesis and Application Of Transition Metal Complexes Omentioning

confidence: 99%

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Synthesis and Application of the Transition Metal Complexes of α-Pyridinyl Alcohols, α-Bipyridinyl Alcohols, α,α’-Pyridinyl Diols and α,α’-Bipyridinyl Diols in Homogeneous Catalysis

2018

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“…We investigated a number of Grubbs 1- and Grubbs 2-type ( 5 ) metal carbenes with pyridinyl alcoholato ligands for the 1-octene metathesis reaction (Fig. 3) [10–14]. The incorporation of pyridinyl-alcoholato ligands in the Grubbs-type precatalysts has shown an increase in the thermal stability, activity and lifetime of the precatalysts when compared to 1 and 2 [10].…”

Section: Introductionmentioning

confidence: 99%

“…The catalytic performance could be further tuned by the incorporation of an electron-donating (e.g., OMe, 5k ) or electron-withdrawing (e.g. Cl, 5i and 5j ) group at the 2- or 4-position of one of the α-phenyl groups of 5d [14]. At 80–110 °C these complexes showed improved catalytic performance in the metathesis of oct-1-ene.…”

Section: Introductionmentioning

confidence: 99%

Catalysis of linear alkene metathesis by Grubbs-type ruthenium alkylidene complexes containing hemilabile α,α-diphenyl-(monosubstituted-pyridin-2-yl)methanolato ligands

Tole¹,

Jordaan²,

Vosloo³

2019

Beilstein J. Org. Chem.

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Four new Grubbs-type precatalysts [RuCl(H2IMes)(O^N)(=CHPh)], where [O^N = α,α-diphenyl-(3-methylpyridin-2-yl)methanolato, α,α-diphenyl-(4-methylpyridin-2-yl)methanolato, α,α-diphenyl-(5-methylpyridin-2-yl)methanolato and α,α-diphenyl-(3-methoxypyridin-2-yl)methanolato] were synthesized and tested for their activity, stability and selectivity in the 1-octene metathesis reaction. Overall the precatalysts showed good activity and high stability for the metathesis of 1-octene at temperatures above 80 °C and up to 110 °C. Selectivities towards the primary metathesis products, i.e., 7-tetradecene and ethene, above 85% were obtained with all the precatalysts at 80 and 90 °C. High selectivities were also observed at 100 °C for the 4-Me- and 3-OMe-substituted precatalysts. With an increase in temperature an increase in isomerisation products and secondary metathesis products were observed with the latter reaching values >20% for the 3-OMe- and 3-Me-substituted precatalysts at 110 and 100 °C, respectively. All the precatalysts exhibits first-order kinetics at 80 °C with the 3-substituted precatalysts the slowest. The behaviour of the 3-substituted precatalysts can be attributed to electronic and steric effects associated with the adjacent bulky phenyl groups.

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Metathesis Reactions in Natural Product Fragments and Total Syntheses

et al. 2022

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The passion of total‐ and fragments syntheses of natural products always remained one of the top priorities among the synthetic chemists worldwide. Due their curiosity toward the complexity of molecules of living nature and their endeavour to imitate them in laboratory; limitless arrays of natural products have been extracted, architecturally‐elucidated, synthesized, and chronicled by utilizing various synthetic methodologies in different fashions. Frequently, the synthesis of complex natural products proceed with inscrutable synthetic challenges, which can be circumvented either by modification of previously developed synthetic methods or by formulating a new one. In this way, a myriad of powerful synthetic reactions have been developed since the genesis of the logic of chemical synthesis. Amongst them, metathesis tactics discovered unexpectedly in the 1950s (Nobel Prize in 2005), have incredibly influenced and changed the landscape of the art of the total and formal synthesis in the last three A. H. Hoveyda, A. R. Zhugralin, me abruptly as compared to other developed transformations or their modified forms. In this particular review article, we envisioned to report a comprehensive detail of the metathetic tools involved in both total and fragments synthesis of natural products in the years 2018 and 2019 along with an overview of 2017.

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Synthesis and Application of Novel Ruthenium Catalysts for High Temperature Alkene Metathesis

Cited by 7 publications

References 49 publications

Synthesis and Application of the Transition Metal Complexes of α-Pyridinyl Alcohols, α-Bipyridinyl Alcohols, α,α’-Pyridinyl Diols and α,α’-Bipyridinyl Diols in Homogeneous Catalysis

Synthesis and Application of the Transition Metal Complexes of α-Pyridinyl Alcohols, α-Bipyridinyl Alcohols, α,α’-Pyridinyl Diols and α,α’-Bipyridinyl Diols in Homogeneous Catalysis

Catalysis of linear alkene metathesis by Grubbs-type ruthenium alkylidene complexes containing hemilabile α,α-diphenyl-(monosubstituted-pyridin-2-yl)methanolato ligands

Metathesis Reactions in Natural Product Fragments and Total Syntheses

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