scholarly journals Ru-based Z-selective metathesis catalysts with modified cyclometalated carbene ligands

2014 ◽  
Vol 5 (10) ◽  
pp. 4091-4098 ◽  
Author(s):  
Sarah M. Bronner ◽  
Myles B. Herbert ◽  
Paresma R. Patel ◽  
Vanessa M. Marx ◽  
Robert H. Grubbs
Keyword(s):  
Olefin Metathesis ◽  
Carbene Ligands ◽  
Metathesis Catalysts

A series of cyclometalated Z-selective ruthenium olefin metathesis catalysts with alterations to the N-heterocyclic carbene (NHC) ligand were prepared.

scholarly journals Consequences of the electronic tuning of latent ruthenium-based olefin metathesis catalysts on their reactivity

2015 ◽  
Vol 11 ◽  
pp. 1458-1468 ◽  
Author(s):  
Karolina Żukowska ◽  
Eva Pump ◽  
Aleksandra E Pazio ◽  
Krzysztof Woźniak ◽  
Luigi Cavallo ◽  
...  
Keyword(s):  
High Temperatures ◽  
Olefin Metathesis ◽  
Minor Amount ◽  
Carbene Ligands ◽  
Enhanced Activity ◽  
Electronic Tuning ◽  
Metathesis Catalysts ◽  
A Minor ◽  
Factor Governing

Two ruthenium olefin metathesis initiators featuring electronically modified quinoline-based chelating carbene ligands are introduced. Their reactivity in RCM and ROMP reactions was tested and the results were compared to those obtained with the parent unsubstituted compound. The studied complexes are very stable at high temperatures up to 140 °C. The placement of an electron-withdrawing functionality translates into an enhanced activity in RCM. While electronically modified precatalysts, which exist predominantly in the trans-dichloro configuration, gave mostly the RCM and a minor amount of the cycloisomerization product, the unmodified congener, which preferentially exists as its cis-dichloro isomer, shows a switched reactivity. The position of the equilibrium between the cis- and the trans-dichloro species was found to be the crucial factor governing the reactivity of the complexes.

Ruthenium Olefin Metathesis Catalysts with N-Heterocyclic Carbene Ligands BearingN-Naphthyl Side Chains

2010 ◽  
Vol 29 (4) ◽  
pp. 775-788 ◽  
Author(s):  
Ludovic Vieille-Petit ◽  
Hervé Clavier ◽  
Anthony Linden ◽  
Sascha Blumentritt ◽  
Steven P. Nolan ◽  
...  
Keyword(s):  
Olefin Metathesis ◽  
Side Chains ◽  
Carbene Ligands ◽  
Metathesis Catalysts

scholarly journals Ruthenium Olefin Metathesis Catalysts Featuring N-Heterocyclic Carbene Ligands Tagged with Isonicotinic and 4-(Dimethylamino)benzoic Acid Rests: Evaluation of a Modular Synthetic Strategy

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5220
Author(s):  
Stefan Czarnocki ◽  
Louis Monsigny ◽  
Michał Sienkiewicz ◽  
Anna Kajetanowicz ◽  
Karol Grela
Keyword(s):  
Benzoic Acid ◽  
Olefin Metathesis ◽  
Ruthenium Catalysts ◽  
Benzoic Acids ◽  
Carbene Ligands ◽  
Synthetic Strategy ◽  
Starting Point ◽  
Brønsted Base ◽  
Metathesis Catalysts

A modular and flexible strategy towards the synthesis of N-heterocyclic carbene (NHC) ligands bearing Brønsted base tags has been proposed and then adopted in the preparation of two tagged NHC ligands bearing rests of isonicotinic and 4-(dimethylamino)benzoic acids. Such tagged NHC ligands represent an attractive starting point for the synthesis of olefin metathesis ruthenium catalysts tagged in non-dissociating ligands. The influence of the Brønsted basic tags on the activity of such obtained olefin metathesis catalysts has been studied.

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.

Ruthenium-Based Olefin Metathesis Catalysts BearingN-Heterocyclic Carbene Ligands

2009 ◽  
Vol 109 (8) ◽  
pp. 3708-3742 ◽  
Author(s):  
Cezary Samojłowicz ◽  
Michał Bieniek ◽  
Karol Grela
Keyword(s):  
Olefin Metathesis ◽  
Carbene Ligands ◽  
Metathesis Catalysts

scholarly journals Specialized Olefin Metathesis Catalysts Featuring Unsymmetrical N-Heterocyclic Carbene Ligands Bearing N-(Fluoren-9-yl) Arm

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 599 ◽  
Author(s):  
Phillip I. Jolly ◽  
Anna Marczyk ◽  
Paweł Małecki ◽  
Damian Trzybiński ◽  
Krzysztof Woźniak ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Olefin Metathesis ◽  
High Selectivity ◽  
State Of The Art ◽  
Heterocyclic Carbenes ◽  
Carbene Ligands ◽  
Structural Motifs ◽  
In Situ Generation ◽  
Metathesis Catalysts

Beneficial structural motifs from two known state-of-the-art olefin metathesis catalysts types, bearing unsymmetrical N-heterocyclic carbenes (uNHCs), were combined into a new hybridized design thereby translating the complementary beneficial reactivity demonstrated by their ‘parent’ complexes to the new N-fluorene derived olefin metathesis catalysts. Two chelating 2-iso-propoxy-benzylidene (Hoveyda-type) and two 3-phenyl-1H-inden-1-ylidene (indenylidene-type) complexes were successfully prepared by in situ generation of either the N′-mesityl (Mes) or N′-diisopropylphenyl (Dipp) derived uNHCs taking advantage of the thermal decomposition of the corresponding 2-(penta-fluorophenyl)-imidazolidines (NHC adducts). The new fluorene-derived catalysts mediate challenging olefin metathesis processes, such as α-olefin self-metathesis, with high selectivity and conversion.

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