Introducing A Podand Motif to Alkyne Metathesis Catalyst Design: A Highly Active Multidentate Molybdenum(VI) Catalyst that Resists Alkyne Polymerization

2011 ◽  
Vol 50 (15) ◽  
pp. 3435-3438 ◽  
Author(s):  
Kuthanapillil Jyothish ◽  
Wei Zhang
Keyword(s):  
Catalyst Design ◽  
Alkyne Metathesis ◽  
Highly Active ◽  
Metathesis Catalyst

Arylene–ethynylene macrocycles: Privileged shape-persistent building blocks for organic materials

2012 ◽  
Vol 84 (4) ◽  
pp. 869-878 ◽  
Author(s):  
Dustin E. Gross ◽  
Ling Zang ◽  
Jeffrey S. Moore
Keyword(s):  
Functional Group ◽  
Organic Materials ◽  
Building Blocks ◽  
Alkyne Metathesis ◽  
Reaction Conditions ◽  
Traditional Methods ◽  
Dynamic Covalent Chemistry ◽  
Highly Active ◽  
Recent Advances ◽  
Metathesis Catalyst

This report details the advances in synthetic strategies toward arylene–ethynylene macrocycles (AEMs). After a brief description of traditional methods, we summarize recent advances based on dynamic covalent chemistry (DCC) whereby a highly active and functional group tolerant alkyne metathesis catalyst yields scalable quantities of AEMs under thermodynamic controlled reaction conditions.

scholarly journals Highly active alkyne metathesis catalysts operating under open air condition

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yanqing Ge ◽  
Shaofeng Huang ◽  
Yiming Hu ◽  
Lei Zhang ◽  
Ling He ◽  
...  
Keyword(s):  
Catalyst System ◽  
Alkyne Metathesis ◽  
Ambient Conditions ◽  
High Moisture ◽  
Highly Active ◽  
Active User ◽  
Metathesis Catalyst ◽  
Cyano Groups ◽  
Metathesis Catalysts ◽  
User Friendly

AbstractAlkyne metathesis represents a rapidly emerging synthetic method that has shown great potential in small molecule and polymer synthesis. However, its practical use has been impeded by the limited availability of user-friendly catalysts and their generally high moisture/air sensitivity. Herein, we report an alkyne metathesis catalyst system that can operate under open-air conditions with a broad substrate scope and excellent yields. These catalysts are composed of simple multidentate tris(2-hydroxyphenyl)methane ligands, which can be easily prepared in multi-gram scale. The catalyst substituted with electron withdrawing cyano groups exhibits the highest activity at room temperature with excellent functional group tolerance (-OH, -CHO, -NO2, pyridyl). More importantly, the catalyst provides excellent yields (typically >90%) in open air, comparable to those operating under argon. When dispersed in paraffin wax, the active catalyst can be stored on a benchtop under ambient conditions without any decrease in activity for one day (retain 88% after 3 days). This work opens many possibilities for developing highly active user-friendly alkyne metathesis catalysts that can function in open air.

scholarly journals Surfactant-Free Colloidal Strategies for Highly Dispersed and Active Supported IrO2 Catalysts: Synthesis and Performance Evaluation for the Oxygen Evolution Reaction

2021 ◽  
Author(s):  
Francesco Bizzotto ◽  
Jonathan Quinson ◽  
Johanna Schröder ◽  
Alessandro Zana ◽  
Matthias Arenz
Keyword(s):  
Supported Catalysts ◽  
Active Phase ◽  
Carbon Support ◽  
Colloidal Dispersions ◽  
Catalyst Design ◽  
Transition Electron Microscopy ◽  
Highly Active ◽  
X Ray Scattering ◽  
And Performance ◽  
Transition Electron

Supported Ir oxide catalysts obtained from surfactant-free colloidal Ir nanoparticles (NPs) synthesized in alkaline methanol (MeOH), ethanol (EtOH), and ethylene glycol (EG) are investigated and compared. The comparison of independent techniques such as transition electron microscopy (TEM), small angle X-ray scattering (SAXS), and electrochemistry allows shedding light on the parameters that affect the dispersion of the active phase as well as the catalytic activity. The colloidal dispersions obtained are suitable to develop supported catalysts with little NP agglomeration on a carbon support leading to highly active catalysts with more than 400 A g<sup>-1</sup><sub>Ir</sub> reached at 1.5 V<sub>RHE</sub> for the OER. While the more common surfactant-free alkaline EG synthesis requires flocculation and re-dispersion leading to Ir loss, the main difference between methanol and ethanol as solvent is related to the dispersibility of the support material. The choice of the suitable monoalcohol determines the maximum achieved Ir loading on the support without detrimental particle agglomeration. This simple consideration on catalyst design can readily lead to significantly improved catalysts.

scholarly journals Dinuclear thiazolylidene copper complex as highly active catalyst for azid–alkyne cycloadditions

2016 ◽  
Vol 12 ◽  
pp. 1566-1572 ◽  
Author(s):  
Anne L Schöffler ◽  
Ata Makarem ◽  
Frank Rominger ◽  
Bernd F Straub
Keyword(s):  
Acetic Acid ◽  
Organic Solvents ◽  
Copper Complex ◽  
Room Temperature ◽  
Active Catalyst ◽  
Catalyst Design ◽  
Ancillary Ligand ◽  
Click Reactions ◽  
Highly Active ◽  
Cost Efficient

A dinuclear N-heterocyclic carbene (NHC) copper complex efficiently catalyzes azide–alkyne cycloaddition (CuAAC) “click” reactions. The ancillary ligand comprises two 4,5-dimethyl-1,3-thiazol-2-ylidene units and an ethylene linker. The three-step preparation of the complex from commercially available starting compounds is more straightforward and cost-efficient than that of the previously described 1,2,4-triazol-5-ylidene derivatives. Kinetic experiments revealed its high catalytic CuAAC activity in organic solvents at room temperature. The activity increases upon addition of acetic acid, particularly for more acidic alkyne substrates. The modular catalyst design renders possible the exchange of N-heterocyclic carbene, linker, sacrificial ligand, and counter ion.

The Fürstner Synthesis of Amphidinolide F

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Amino Alcohol ◽  
Aldol Condensation ◽  
Free Acid ◽  
The Other ◽  
Unsaturated Ester ◽  
Alkyne Metathesis ◽  
Max Planck ◽  
Ring Closing Metathesis ◽  
Enantiomerically Pure ◽  
Metathesis Catalyst

The amphidinolides, having zero, one, or (as exemplified by amphidinolide F 3) two tetrahydrofuran rings, have shown interesting antineoplastic activity. It is a tribute to his development of robust Mo catalysts for alkyne metathesis that Alois Fürstner of the Max-Planck-Institut für Kohlenforschung Mülheim could with confidence design (Angew. Chem. Int. Ed. 2013, 52, 9534) a route to 3 that relied on the ring-closing metathesis of 1 to 2 very late in the synthesis. Three components were prepared for the assembly of 1. Julia had already reported (J. Organomet. Chem. 1989, 379, 201) the preparation of the E bromodiene 5 from the sulfone 4. The alcohol 7 was available by the opening of the enantiomerically-pure epoxide 6 with propynyl lithium, followed by oxidation following the Pagenkopf pro­tocol. Amino alcohol-directed addition of the organozinc derived from 5 to the alde­hyde from oxidation of 7 completed the assembly of 8. Addition of the enantiomer 10 of the Marshall butynyl reagent to 9 followed by protection, oxidation to 11, and addition of, conveniently, the other Marshall enan­tiomer 12 led to the protected diol 13. Silylcupration–methylation of the free alkyne set the stage for selective desilylation and methylation of the other alkyne. Iodination then completed the trisubstituted alkene of 14. Methylation of the crystalline lactone 15, readily prepared from D-glutamic acid, led to a mixture of diastereomers. Deprotonation of that product followed by an aque­ous quench delivered 16. Reduction followed by reaction with the phosphorane 17 gave the unsaturated ester, that cyclized with TBAF to the crystalline 18. The last ste­reogenic center of 22 was established by proline-mediated aldol condensation of the aldehyde 19 with the ketone 20. To assemble the three fragments, the ketone of 21 was converted to the enol triflate and thence to the alkenyl stannane. Saponification gave the free acid 22, that was acti­vated, then esterified with the alcohol 18. Coupling of the stannane with the iodide 14 followed by removal of the TES group led to the desired diyne 1. It is noteworthy that the Mo metathesis catalyst is stable enough to tolerate the free alcohol of 1 in the cyclization to 2.

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