Carboxamide substituted tetramethylcyclopentadiene - synthesis, characterisation and its iridium(III) complex catalysed reduction of imines DOI
Joseph M. Mwansa,

Matthew Stirling,

Gemma Sweeney

и другие.

Dalton Transactions, Год журнала: 2022, Номер 51(7), С. 2696 - 2707

Опубликована: Янв. 1, 2022

The novel dimeric iodo-iridium(III) complex, [Ir(Cp*CONMe2)I2]2, (Cp*CONMe2 = η5-N,N-2,3,4,5-hexamethylcyclopenta-2,4-diene carboxamide) bearing an amide moiety within the tetramethylcyclopentadiene ring, has been synthesised and characterised. ligand Cp*CONMe2 is as two regioisomers, however 2-substituted isomer exists distinguishable conformers due to restricted rotation about carbonyl carbon ring carbon. relative acidities of Cp* are compared by their rates H/D exchange. iridium complex N,N-2,3,4,5-hexamethylcyclopenta-2-4-diene carboxamide [IrCp*CONMe2] (R,R)-1,2-diphenyl-N'-tosylethane-1,2-diamine ((R,R)-TsDPEN) evaluated in transfer hydrogenation imines under acidic conditions - a 5 : 2 molar ratio formic acid triethylamine hydride source for 1-methyl-3,4-dihydroisoquinoline (DHIQ) its 6,7-dimethoxy derivative acetonitrile. A decreasing enantiomeric excess with reaction progress attributed different kinetic orders formation product amine enantiomers. pseudo zero-order R-amine may be pre-steady-state less stable form diastereomeric catalyst. By contrast, both amines from 1-fluorinated methyl DHIQs substrates reduction formed first-order processes.

Язык: Английский

Cycloiridated Helicenes as Chiral Catalysts in the Asymmetric Transfer Hydrogenation of Imines DOI
Daisuke Sakamoto,

Isabel Gay Sánchez,

Jiří Rybáček

и другие.

ACS Catalysis, Год журнала: 2022, Номер 12(17), С. 10793 - 10800

Опубликована: Авг. 19, 2022

The asymmetric synthesis of optically pure and conformationally locked oxabenzo[5]helicenes bearing pyridin-2-yl or isoquinolin-3-yl substituents their transformation into the corresponding cycloiridated organometallics are described. These helically chiral Cp*IrIII(X)C,N-complexes (X = Cl, I) also contain a configurationally unstable pseudotetrahedral iridium center. This center undergoes epimerization at room temperature, its relative stereochemistry, especially in solid state, depends on nature coordinated ligands. Cycloiridated helicenes were used transfer hydrogenation prochiral aromatic imines with formic acid/triethylamine to reach up 96:4 er. It is assumed that chirality controlled by auxiliary helix rather than IrIII stereogenic iridacycles.

Язык: Английский

Процитировано

34
Recent advances in 2-methylfuran production via catalytic transfer hydrogenation of biomass-derived furfural DOI
Debarun Banerjee, Aloka Kumar Sahu, Jack K. Clegg

и другие.

Chemical Engineering Journal, Год журнала: 2024, Номер 493, С. 152552 - 152552

Опубликована: Май 25, 2024

Язык: Английский

Процитировано

8
Origin of Stereoselectivity in FLP-Catalyzed Asymmetric Hydrogenation of Imines DOI Creative Commons
Andrea Hamza, Kristina Sorochkina,

Bianka Kótai

и другие.

ACS Catalysis, Год журнала: 2020, Номер 10(23), С. 14290 - 14301

Опубликована: Ноя. 23, 2020

Development of metal-free strategies for stereoselective hydrogenation unsaturated substrates is particular interest in asymmetric synthesis. The emerging chemistry frustrated Lewis pairs offers a promising approach along this line as demonstrated by recent achievements. However, the stereocontrol elements these reactions are not clearly recognized thus far. Herein, we analyze origin stereoinduction direct imines catalyzed set chiral boranes. We use tools computational to describe elementary steps catalytic cycle, and pay special attention stereoselectivity-determining hydride transfer process. enantioselectivities predicted applied very good agreement with previous experimental observations. find that stereoselectivity governed thermodynamically less favored conformer borohydride intermediate experimentally observed form. most transition states stabilized specific aryl–aryl alkyl–aryl noncovalent interactions, which play an important role stereoinduction. This insight exploited proposing additional borane variants improve enantioselectivity, could be

Язык: Английский

Процитировано

31
Iridium‐Catalyzed Acid‐Assisted Hydrogenation of Oximes to Hydroxylamines DOI
Josep Mas‐Roselló, Christopher J. Cope,

Eric Tan

и другие.

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(28), С. 15524 - 15532

Опубликована: Апрель 22, 2021

Abstract We found that cyclometalated cyclopentadienyl iridium(III) complexes are uniquely efficient catalysts in homogeneous hydrogenation of oximes to hydroxylamine products. A stable iridium C,N‐chelation is crucial, with alkoxy‐substituted aryl ketimine ligands providing the best catalytic performance. Several Ir‐complexes were mapped by X‐ray crystal analysis order collect steric parameters might guide a rational design even more active catalysts. broad range and oxime ethers activated stoichiometric amounts methanesulfonic acid reduced at room temperature, remarkably without cleavage fragile N−O bond. The exquisite functional group compatibility our system was further demonstrated additive tests. Experimental mechanistic investigations support an ionic platform, suggest role for Brønsted beyond proton source. Our studies provide deep understanding this novel acidic may facilitate its improvement application other challenging substrates.

Язык: Английский

Процитировано

27
Overview of the Synthesis and Catalytic Reactivity of Transition Metal Complexes Based on C═P Bond Systems DOI Creative Commons
Aleksandra Ziółkowska,

Justyna Doroszuk,

Łukasz Ponikiewski

и другие.

Organometallics, Год журнала: 2023, Номер 42(7), С. 505 - 537

Опубликована: Март 20, 2023

This report provides an overview of the use phosphaalkenes (C═P) in syntheses various complexes. Going through successive complexes containing d-block metals, we sought how this area chemistry was formed over years. Additionally, work contains information on possible coordination types and means constructing In addition, review reveals reactivities phosphaalkene with a strong emphasis catalytic properties.

Язык: Английский

Процитировано

11
A Transfer Hydrogenation Approach to Activity-Based Sensing of Formate in Living Cells DOI
Steven W. M. Crossley, Logan Tenney, Vanha N. Pham

и другие.

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(13), С. 8865 - 8876

Опубликована: Март 12, 2024

Formate is a major reactive carbon species in one-carbon metabolism, where it serves as an endogenous precursor for amino acid and nucleic biosynthesis cellular source of NAD(P)H. On the other hand, aberrant elevations formate are connected to progression serious diseases, including cancer Alzheimer's disease. Traditional methods detection biological environments often rely on sample destruction or extensive processing, resulting loss spatiotemporal information. To help address these limitations, here we present design, synthesis, evaluation first-generation activity-based sensing system live-cell imaging that relies iridium-mediated transfer hydrogenation chemistry. facilitates aldehyde-to-alcohol conversion various fluorophore scaffolds enable fluorescence this unit, through two-color ratiometric response with internal calibration. The two-component probe can detect changes levels living cells high selectivity over potentially competing analytes. Moreover, visualize fluxes alterations pathways cell-based models human colon cancer, presaging potential utility chemical approach continuum between metabolism signaling diseases.

Язык: Английский

Процитировано

3
Hydrogen production based on hexacoordinated cobalt scaffolds as electrocatalysts for acid-proton reduction: Electrochemistry and mechanisms DOI
Ibukun Oluwaseun Shotonwa,

Onome Ejeromedoghene,

Adedoyin Oluseyi Adesoji

и другие.

Journal of Electroanalytical Chemistry, Год журнала: 2024, Номер 963, С. 118228 - 118228

Опубликована: Апрель 21, 2024

Язык: Английский

Процитировано

3
Homogeneous and heterogeneous strategies of enantioselective hydrogenation: Critical evaluation and future prospects DOI Creative Commons
Aleksei N. Marianov, Yijiao Jiang, Alfons Baiker

и другие.

Chem Catalysis, Год журнала: 2023, Номер 3(7), С. 100631 - 100631

Опубликована: Май 20, 2023

Язык: Английский

Процитировано

7
Recent Development in the Synthesis and Catalytic Application of Iridacycles DOI Creative Commons
Zhenyu Chen, Ayşecik Kaçmaz, Jianliang Xiao

и другие.

The Chemical Record, Год журнала: 2021, Номер 21(6), С. 1506 - 1534

Опубликована: Май 3, 2021

Abstract Cyclometallated complexes are well‐known and have found many applications. This article provides a short review on the progress made in synthesis application to catalysis of cyclometallated half‐sandwich Cp*Ir(III) (Cp*: pentamethylcyclopentadienyl) since 2017. Covered iridacycles featuring conventional C,N chelates less common metallocene carbene‐derived C,C ligands. is followed by an overview studies their applications ranging from asymmetric hydrogenation, transfer hydrosilylation dehydrogenation.

Язык: Английский

Процитировано

12
First‐Row Transition Metal‐Catalyzed Single Hydroelementation of N‐Heteroarenes DOI
Sehoon Park

ChemCatChem, Год журнала: 2023, Номер 16(5)

Опубликована: Ноя. 29, 2023

Abstract Catalytic partial reduction of N‐heteroarenes with H 2 or H[E] (E=Si, B‐based) has been a useful and general method for synthesis broad range dihydropyridines (DHP) dihydroquinolines (DHQ). In recent seven years, one the most notable advances in this context is being able to utilize earth‐abundant inexpensive first‐row transition metal‐based catalytic systems. These procedures are generally considered more environmentally benign sustainable when compared conventional systems relying on precious metals. This Review describes 20 molecular based metals selective single hydroelementation pyridines quinolines surrogate, hydrosilanes, hydroboranes providing 1,2‐ 1,4‐dihydropyridines ‐dihydroquinolines. The observed reaction profiles such as scope activity briefly presented, while proposed working modes over series elemental steps – H−[E] bond cleavage, hydride (H − ) hydrogen atom (H⋅) transfer, product release, discussed detail basis experimental and/or computational mechanistic observations insights.

Язык: Английский

Процитировано

5