scholarly journals Enantioselective Catalyst Systems from Copper(II) Triflate and BINOL-Silanediol

2018 ◽  
Vol 24 (28) ◽  
pp. 7123-7127 ◽  
Author(s):  
Yong Guan ◽  
Jonathan W. Attard ◽  
Michael D. Visco ◽  
Thomas J. Fisher ◽  
Anita E. Mattson
Keyword(s):  
Enantioselective Catalyst ◽  
Catalyst Systems

Computationally-Guided Investigation of Dual Amine/pi Lewis Acid Catalysts for Direct Additions of Aldehydes and Ketones to Unactivated Alkenes and Alkynes

2020 ◽  
Author(s):  
Eric Greve ◽  
Jacob D. Porter ◽  
Chris Dockendorff
Keyword(s):  
Lewis Acid ◽  
Density Functional ◽  
Acid Catalyst ◽  
Metal Catalyst ◽  
Catalyst Poisoning ◽  
Lewis Acid Catalysts ◽  
Metal Ligands ◽  
Aldehydes And Ketones ◽  
Lewis Acid Catalyst ◽  
Catalyst Systems

Dual amine/pi Lewis acid catalyst systems have been reported for intramolecular direct additions of aldehydes/ketones to unactivated alkynes and occasionally alkenes, but related intermolecular reactions are rare and not presently of significant synthetic utility, likely due to undesired coordination of enamine intermediates to the metal catalyst. We reasoned that bulky metal ligands and bulky amine catalysts could minimize catalyst poisoning and could facilitate certain examples of direct intermolecular additions of aldehyde/ketones to alkenes/alkynes. Density Functional Theory (DFT) calculations were performed that suggested that PyBOX-Pt(II) catalysts for alkene/alkyne activation could be combined with MacMillan’s imidazolidinone organocatalyst for aldehyde/ketone activation to facilitate desirable C-C bond formations, and certain reactions were calculated to be more exergonic than catalyst poisoning pathways. As calculated, preformed enamines generated from the MacMillan imidazolidinone did not displace ethylene from a biscationic (<i>t</i>-Bu)PyBOX-Pt<sup>2+</sup>complex, but neither were the desired C-C bond formations observed under several different conditions.

Computationally-Guided Investigation of Dual Amine/pi Lewis Acid Catalysts for Direct Additions of Aldehydes and Ketones to Unactivated Alkenes and Alkynes

2020 ◽  
Author(s):  
Eric Greve ◽  
Jacob D. Porter ◽  
Chris Dockendorff
Keyword(s):  
Lewis Acid ◽  
Density Functional ◽  
Acid Catalyst ◽  
Metal Catalyst ◽  
Catalyst Poisoning ◽  
Lewis Acid Catalysts ◽  
Metal Ligands ◽  
Aldehydes And Ketones ◽  
Lewis Acid Catalyst ◽  
Catalyst Systems

Dual amine/pi Lewis acid catalyst systems have been reported for intramolecular direct additions of aldehydes/ketones to unactivated alkynes and occasionally alkenes, but related intermolecular reactions are rare and not presently of significant synthetic utility, likely due to undesired coordination of enamine intermediates to the metal catalyst. We reasoned that bulky metal ligands and bulky amine catalysts could minimize catalyst poisoning and could facilitate certain examples of direct intermolecular additions of aldehyde/ketones to alkenes/alkynes. Density Functional Theory (DFT) calculations were performed that suggested that PyBOX-Pt(II) catalysts for alkene/alkyne activation could be combined with MacMillan’s imidazolidinone organocatalyst for aldehyde/ketone activation to facilitate desirable C-C bond formations, and certain reactions were calculated to be more exergonic than catalyst poisoning pathways. As calculated, preformed enamines generated from the MacMillan imidazolidinone did not displace ethylene from a biscationic (<i>t</i>-Bu)PyBOX-Pt<sup>2+</sup>complex, but neither were the desired C-C bond formations observed under several different conditions.

A New Computational Interface for Catalysis

2019 ◽  
Author(s):  
Pavlo Kravchenko ◽  
Craig Plaisance ◽  
David Hibbitts
Keyword(s):  
Zeolite Catalyst ◽  
Metal Ceramic ◽  
Catalyst Systems ◽  
Computational Catalysis

This manuscript outlines the utility and power of our computational catalysis interface. This interface has been developed by our group and used extensively to study metal, ceramic, and zeolite catalyst systems.

Employing Exfoliated Graphite as Novel Support Material for Heterogeneous Model Catalysts

2019 ◽  
Author(s):  
Moritz Wolf ◽  
Nico Fischer ◽  
Michael Claeys
Keyword(s):  
Surface Area ◽  
Graphite Powder ◽  
Model Catalysts ◽  
Model Systems ◽  
Exfoliated Graphite ◽  
Support Material ◽  
Heterogeneous Model ◽  
Support Materials ◽  
Metal Support Interaction ◽  
Catalyst Systems

<p>The inert nature of graphitic samples allows for characterisation of rather isolated supported nanoparticles in model catalysts, as long as sufficiently large inter-particle distances are obtained. However, the low surface area of graphite and the little interaction with nanoparticles result in a challenging application of conventional preparation routes in practice. In the present study, a set of graphitic carbon materials was characterised in order to identify potential support materials for the preparation of model catalyst systems. Various sizes of well-defined Co<sub>3</sub>O<sub>4</sub> nanoparticles were synthesised separately and supported onto exfoliated graphite powder, that is graphite after solvent-assisted exfoliation <i>via</i> ultrasonication resulting in thinner flakes with increased specific surface area. The developed model catalysts are ideally suited for sintering studies of isolated nano-sized cobaltous particles as the graphitic support material does not provide distinct metal-support interaction. Furthermore, the differently sized cobaltous particles in the various model systems render possible studies on structural dependencies of activity, selectivity, and deactivation in cobalt oxide or cobalt catalysed reactions.</p>

Synthesis of Phosphonates, Phosphinates and Tertiary Phosphine Oxides by Pd- or Ni-Catalyzed Microwave-Assisted P–C Coupling Reactions without the Addition of Conventional Ligands

2021 ◽  
Vol 25 ◽  
Author(s):  
Réka Henyecz ◽  
György Keglevich
Keyword(s):  
Tautomeric Form ◽  
Catalyst Precursor ◽  
Coupling Reactions ◽  
Optimum Conditions ◽  
Pd Catalysts ◽  
Catalyst Complex ◽  
Two Factors ◽  
Dialkyl Phosphites ◽  
Catalyst Systems ◽  
P Ligands

Abstract: Microwave (MW)-assistance may be a powerful tool also in the Hirao P–C coupling reactions of vinyl/aryl halides with dialkyl phosphites in the presence of Pd-catalysts/P-ligands elaborated forty years ago. This review surveys the development of this reaction by showing the expansion of the reagents and catalysts, as well as the information accumulated. The stress was laid on the “green” aspects, the simplification of the catalyst systems, and the reliable mechanistic details in order to be able to establish the optimum conditions. The best protocol involves the use of some excess of the >P(O)H reagent to ensure the PdII→Pd0 reduction and, via its trivalent tautomeric form (>POH) also the P-ligand. The overall rate is the result of two factors, the activity of the catalyst complex formed, and the reactivity of the reactants in the P–C coupling reactions. Both components are influenced by the nature of the aryl substituents in Ar2P(O)H. NiII salts may also be used as the catalyst precursor, however, despite the PdII→Pd0→PdII route, in this case, a NiII→NiIV→NiII sequence was proved.

Electrolysis of Ionic Liquids. A Possible Keystone for the Achievement of Green Solvent-Catalyst Systems

2013 ◽  
Vol 17 (3) ◽  
pp. 204-219 ◽  
Author(s):  
Marta Feroci ◽  
Isabella Chiarotto ◽  
Achille Inesi
Keyword(s):  
Ionic Liquids ◽  
Green Solvent ◽  
Catalyst Systems

Ruthenium-catalysed Hydroxycarbonylation of Olefins

2021 ◽  
Author(s):  
Ricarda Dühren ◽  
Peter Kucmierczyk ◽  
Ralf Jackstell ◽  
Robert Franke ◽  
Matthias Beller
Keyword(s):  
State Of The Art ◽  
Palladium Complexes ◽  
Catalyst Systems

State-of-the-art catalyst systems for hydroxy- and alkoxycarbonylations of olefins make use of palladium complexes. In this work, we report a complementary ruthenium-catalysed hydroxycarbonylation of olefins applying an inexpensive Ru-precursor (Ru3(CO)12)...

Direct synthesis of jet fuel range dicycloalkane by the aqueous phase hydrodeoxygenation of polycarbonate

2021 ◽  
Author(s):  
Lulin Wang ◽  
Guangyi Li ◽  
Cong Yu ◽  
Ai-Qin Wang ◽  
Xiaodong Wang ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Direct Synthesis ◽  
Jet Fuel ◽  
Catalyst Systems ◽  
First Time

For the first time, propane-2,2-diyldicyclohexane, a jet fuel range C15 dicycloalkane was directly produced by the aqueous-phase hydrodeoxygenation (APHDO) of polycarbonate (PC). Among the investigated catalyst systems, a mixture of...

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