Metathesis Catalysts with Fluorinated Unsymmetrical NHC Ligands

Masoud, Salekh M.; Mailyan, Artur K.; Dorcet, Vincent; Roisnel, Thierry; Dixneuf, Pierre H.; Bruneau, Christian; Osipov, Sergey N.

doi:10.1021/om501077w

Cited by 28 publications

(19 citation statements)

References 121 publications

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“…The found conditions have proved to be suitable for the preparation of two more tricyclic imidazolinium salts bearing substituents of different bulkiness. For these purposes fluorinated aniline 2b with free ortho ‐position (R = H) and amidoaldehyde 5b with bulky 2,6‐diisopropylphenyl group (Ar = DIPP) have been applied as starting materials. As result, the corresponding salts 7b and 7c were obtained in acceptable yields (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Recently we have developed an efficient route to the new family of unsymmetrical N , N ‐diaryl imidazolium and imidazolinium salts with bulky hexafluoroisopropylalkoxy [(CF 3 ) 2 (OR)C‐] group in one of the N ‐aryl substituents and investigated their potential as universal precursors of the corresponding NHC ligands for metal catalysis. Some of ruthenium‐alkylidene complexes bearing these ligands demonstrated a good performance in olefin RCM and cross‐metathesis (CM) . With the aim of further evaluating the effects of bulky fluorinated substituents installed in unsymmetrical NHC ligand on the activity of the resulting metathesis precatalysts, now we want to disclose the synthesis of novel imidazoline‐based tricyclic NHC precursors and the corresponding ruthenium carbene complexes as well as preliminary evaluation of their catalytic activity (Scheme ).…”

Section: Introductionmentioning

confidence: 99%

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Ruthenium‐Alkylidene Complexes with Sterically Rigid Fluorinated NHC Ligands

et al. 2018

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An efficient procedure for the preparation of novel olefin metathesis catalysts of Grubbs‐Hoveyda type bearing sterically rigid NHC ligands has been developed. A preliminary evaluation of their catalytic activity has been performed on representative olefin metathesis reactions, such as RCM of malonates as well as self‐metathesis of allylbenzene. As result, it was found that along with excellent robustness, new complexes demonstrate remarkable activity in metathesis of allylbenzene, outperforming commercially available Grubbs‐Hoveyda catalyst in terms of yield and regioselectivity.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ruthenium‐Alkylidene Complexes with Sterically Rigid Fluorinated NHC Ligands

et al. 2018

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“…The chemical shifts are frequency referenced relative to the residual undeuterated solvent peaks. 2‐(2‐Amino‐3,5‐dimethylphenyl)‐1,1,1,3,3,3‐hexafluoro‐propan‐2‐ol ( 3 ), 5‐acetoxy‐3‐mesityl‐4,5‐dihydrooxazol‐3‐ium tetrafluoroborate ( 4 ), and [PdCl 2 (3‐ClPy) 2 ] were synthesized according to literature procedures. All crystals suitable for X‐ray experiments were obtained from the CH 2 Cl 2 /hexane solvent mixtures (1:1) at −5 °C.…”

Section: Methodsmentioning

confidence: 99%

“…We have recently elaborated ana ccess to unsymmetrical 1,3-bis(aryl)-4,5-dihydroimidazolium salts bearing ah exafluoroisopropylmethoxy group at the N-aryl moiety (compound 1, Figure 2) and have demonstrated their further potential to be used as precursors of the corresponding NHC ligandsf or the synthesis of an ew family of metathesis catalysts. [17] Now,w e wish to report on an efficient route to sterically demanding un-symmetrical 1,3-bis(aryl)-imidazolium salts comprising ah exafluoroisopropylalkoxy group [(CF 3 ) 2 (OR)CÀ]a tt he ortho position of the N-aryl substituent (compound 2,F igure 2) as well as their application for the preparation of new metal complexes. The combination of two bulky lipophilic CF 3 groups with the anionic alkoxy group could generate ac helating ligand able to give rise to complexes with increased stability, steric rigidity,a nd enhanced solubility in common organic solvents (or monomers).…”

Section: Introductionmentioning

confidence: 99%

Fluorinated Unsymmetrical N,N′‐Diaryl Imidazolium Salts—New Functionalized NHC‐Ligand Precursors

Topchiy

Zotova

Masoud

et al. 2017

Chemistry A European J

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An efficient and scaled-up synthesis of the imidazol-2-ylidene-based unsymmetrical NHC precursors bearing the sterically demanding hexafluoroisopropylalkoxy group [(CF ) (OR)C-] at the ortho position of the N-aryl substituent was developed. The key step of the method involved the transformation of a Mes-substituted oxazolinium tetrafluoroborate salt through the reaction with the corresponding binucleophilic fluoroalkyl-substituted aniline. The subsequent post-modification of the resulting hydroxyl-containing salt through a simple one-step O-alkylation protocol provided access to a new family of unsymmetrical fluorinated NHC precursors. These compounds were successfully utilized for the preparation of several novel metal complexes. The molecular structures of some NHC precursors and their metal complexes have been unambiguously characterized by single-crystal X-ray diffraction analysis. A preliminary evaluation of the catalytic activity of the palladium complexes was performed on a Buchwald-Hartwig amination reaction. As a result, two PEPPSI-type (PEPPSI=pyridine-enhanced pre-catalyst preparation stabilization and initiation) Pd complexes have demonstrated promising activity in alkane solvents.

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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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Metathesis Catalysts with Fluorinated Unsymmetrical NHC Ligands

Cited by 28 publications

References 121 publications

Ruthenium‐Alkylidene Complexes with Sterically Rigid Fluorinated NHC Ligands

Ruthenium‐Alkylidene Complexes with Sterically Rigid Fluorinated NHC Ligands

Fluorinated Unsymmetrical N,N′‐Diaryl Imidazolium Salts—New Functionalized NHC‐Ligand Precursors

Metathesis Reactions in Natural Product Fragments and Total Syntheses

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