Beyond Continuum Solvent Models in Computational Homogeneous Catalysis

Topics in Catalysis, Journal Year: 2021, Volume and Issue: 65(1-4), P. 118 - 140

Published: Nov. 16, 2021

Abstract In homogeneous catalysis solvent is an inherent part of the catalytic system. As such, it must be considered in computational modeling. The most common approach to include effects quantum mechanical calculations by means continuum models. When they are properly used, average efficiently captured, mainly those related with polarity. However, neglecting atomistic description molecules has its limitations, and models all alone cannot applied whatever situation. many cases, inclusion explicit system mandatory. purpose this article highlight through selected examples what reasons that urge go beyond employment micro-solvated (cluster-continuum) fully models, way setting limits catalysis. These showcase calculation not only can improve already known mechanisms but yield new mechanistic views a reaction. With aim systematizing use after discussing success limitations issues coordination dynamics, reactions involving small, charged species, as well protic solvents role reagent itself successively considered.

Language: Английский

---

Alkali Metal Alkoxides in Noyori‐Type Hydrogenations

European Journal of Inorganic Chemistry, Journal Year: 2021, Volume and Issue: 2021(47), P. 4884 - 4889

Published: Sept. 21, 2021

Abstract This minireview discusses the accelerative role of alkali metal alkoxides in two important catalytic processes: hydrogenation ketones and esters with Noyori‐type molecular catalysts. Here I offer my perspective on unique mechanistic aspects these reactions – a subject that remains controversial often misunderstood.

Language: Английский

---

Performance Analysis of CP2K Code for Ab Initio Molecular Dynamics on CPUs and GPUs

Journal of Chemical Information and Modeling, Journal Year: 2022, Volume and Issue: 62(10), P. 2378 - 2386

Published: April 22, 2022

Using a realistic molecular catalyst system, we conduct scaling studies of ab initio dynamics simulations using the popular CP2K code on both Intel Xeon CPU and NVIDIA V100 GPU architectures. Additional performance improvements were gained by finding more optimal process placement affinity settings. Statistical methods employed to understand changes in spite variability runtime for each timestep. Ideal conditions runs found when running at least four MPI ranks per node, bound evenly across socket. This study also showed that fully utilizing processing cores, with one OpenMP thread core, performed better than reserving cores system. The CPU-only scaled 70% or ideal up 10 compute nodes, after which returns began diminish quickly. Simulations single 40-core node two GPUs acceleration achieved over 3.7× speedup compared fastest 36-core version. These same 13% time five nodes.

Language: Английский

---

Access to Secondary Amines through Hydrogen Autotransfer Reaction Mediated by KO^tBu

European Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 27(11)

Published: Dec. 18, 2023

Abstract We report herein an N ‐alkylation reaction of amines with alcohols through a hydrogen autotransfer reaction. Unlike other catalytic systems containing transition metals or additives, potassium tertiary butoxide was found to be unique and effective catalyst for synthesizing secondary amines. The role the K + ion intermediates were studied under control experiments by theoretical calculations. general tolerates series functional groups, providing convenient method synthesize ‐alkylated compounds.

Language: Английский

---

KO^tBu Mediated Alcohol Dehydrogenation Strategy: Synthesis of 2‐Aryl Quinazolinones

ChemistrySelect, Journal Year: 2024, Volume and Issue: 9(11)

Published: March 12, 2024

Abstract Herein we report an atom‐economical, transition metal‐free method for synthesizing 2‐aryl quinazolinones through a cascade annulation of 2‐amino benzamide and benzyl alcohol. The reaction proceeds via KO t Bu‐mediated acceptorless alcohol dehydrogenation pathways. procedure tolerates wide variety functional groups provides convenient the synthesis quinazolinones. Mechanistic insights by experiments DFT calculations lead to unveil mechanism.

Language: Английский

---

Double Direct C–H Bond Arylation of Thiophenes with Aryl Chlorides Catalyzed by the N-Heterocyclic Carbene-PdCl₂-1-methylimidazole Complex

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(17), P. 12533 - 12539

Published: Aug. 21, 2024

With the combination of

Language: Английский

---

Production of Benzene by the Hydrodemethylation of Toluene with Carbon‐Supported Potassium Hydride

ChemSusChem, Journal Year: 2022, Volume and Issue: 16(2)

Published: Nov. 29, 2022

The hydrodemethylation (HDM) of toluene to benzene is an industrial process performed at elevated temperatures (≈500 °C and higher). Here, it was reported that heating graphite-supported potassium hydride (KH/C) with under H2 atmosphere provided already 125-250 °C. Depending on the pressure, reaction either substoichiometric ( ≤11 bar) or catalytic ≥50 respect KH, indicating KH may serve as a radical chain initiator. At 250 °C, selectivity 98 63 % when using 6 80 bar , respectively, owing competing formation cyclohexane methylcyclohexane high pressure. used KH/C material amenable recycling without notable loss in yield benzene.

Language: Английский

---

Transition Metal‐Free Aerobic Oxidation of Aryl Secondary and Primary Alcohols to Carbonyl Compounds in Open Air

ChemistrySelect, Journal Year: 2022, Volume and Issue: 7(3)

Published: Jan. 19, 2022

Abstract The ketones and benzoic acids are very useful chemicals as the precursors intermediates in both laboratory synthetic industrial applications, which usually obtained by selective catalytic oxidation of alcohols using a amount certain expensive oxidants or metal catalysts. Here, an efficient practical aryl secondary primary to corresponding carbonyl compounds NaO t Bu open air at room temperature has been developed. And utilizing Bu/air/ toluene, series were from high yields, respectively. More importantly, most substrates with electron‐withdrawing electron‐donating groups could be converted products excellent yields. Furthermore, practicality reaction was demonstrated through 1.0 gram‐scale yield.

Language: Английский

---

Diastereoselective Construction of Tetrahydro-Dispiro[indolinone-3,2′-pyran-5′,4″-pyrazolone] Scaffolds via an Oxa-Michael Cascade [4 + 2] Annulation Reaction

The Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 88(22), P. 15540 - 15550

Published: Sept. 16, 2022

A straightforward metal-free oxa-Michael cascade [4 + 2] annulation reaction was established between isatin-derived Morita–Baylis–Hillman (Is-MBH) alcohols with alkylidene pyrazolones to access structural diverse tetrahydro-dispiro[indolinone-3,2′-pyran-5′,4″-pyrazolone] scaffolds bearing two tertiary and quaternary stereocenters. The Is-MBH alcohol utilized as an donor for the first time a new approach in highly atom-economical transformations. This method offered wide range of bioinspired novel tetrahydro-dispirooxindole-pyran-pyrazolone derivatives excellent yields (up 96%) diastereoselectivities >20:1) shorter (15 min).

Language: Английский

---

Tandem Hydrogen‐Borrowing Dehydrogenative Coupling and Hydrodefluorination

Advanced Synthesis & Catalysis, Journal Year: 2024, Volume and Issue: 366(8), P. 1809 - 1819

Published: Feb. 7, 2024

Abstract Dehydrogenative coupling (DC) is an attractive approach to constructing new C−N bonds using alcohols as electrophiles. In ‘hydrogen‐borrowing’ variants of DC, the H 2 liberated can be used re‐hydrogenate unsaturated intermediates produce saturated products. Here, we show how so‐generated also replace fluorine atoms with hydrogens in CF 3 groups a tandem dehydrogenative coupling/hydrodefluorination process.

Language: Английский

---