Bioinspired Non‐Heme Mn Catalysts for Regio‐ and Stereoselective Oxyfunctionalizations with H₂O₂

Chemistry - A European Journal, Journal Year: 2023, Volume and Issue: 29(66)

Published: Aug. 29, 2023

Abstract In recent years, metalloenzymes‐mediated highly selective oxidations of organic substrates under mild conditions have been inspiration for developing synthetic bioinspired catalyst systems, capable conducting such processes in the laboratory (and, future, industry), relying on easy‐to‐handle and environmentally benign oxidants as H 2 O . To date, non‐heme manganese complexes with chiral bis ‐amino‐ ‐pyridylmethyl structurally related ligands are considered possessing highest potential, having demonstrated ability to mediate a variety chemo‐ stereoselective oxidative transformations, epoxidations, C(sp 3 )‐H hydroxylations ketonizations, desymmetrizations, kinetic resolutions, etc. Furthermore, past few years Mn based catalysts become major platform studies focused getting insight into molecular mechanisms oxidant activation (stereo)selective oxygen transfer, testing non‐traditional hydroperoxide oxidants, engineering catalytic sites enzyme‐like substrate recognition‐based selectivity, exploration regioselectivity trends oxidation biologically active natural origin. This contribution summarizes progress catalyzed C‐H oxygenative transformations substrates, achieved essentially 5 (late 2018–2023).

Language: Английский

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Mononuclear Non-Heme Manganese-Catalyzed Enantioselective cis-Dihydroxylation of Alkenes Modeling Rieske Dioxygenases

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(50), P. 27626 - 27638

Published: Dec. 8, 2023

The practical catalytic enantioselective cis-dihydroxylation of olefins that utilize earth-abundant first-row transition metal catalysts under environmentally friendly conditions is an important yet challenging task. Inspired by the reactions catalyzed Rieske dioxygenases and non-heme iron models, we report biologically inspired catalysis employs inexpensive readily available mononuclear manganese complex bearing a tetradentate nitrogen-donor ligand aqueous hydrogen peroxide (H2O2) potassium peroxymonosulfate (KHSO5) as terminal oxidants. A wide range are efficiently oxidized to enantioenriched cis-diols in practically useful yields with excellent selectivity enantioselectivity (up 99% ee). Mechanistic studies, such isotopically 18O-labeled water experiments, density functional theory (DFT) calculations support manganese(V)-oxo-hydroxo (HO–MnV═O) species, which formed via water-assisted heterolytic O–O bond cleavage putative manganese(III)-hydroperoxide manganese(III)-peroxysulfate precursors, active oxidant effects olefins; this reminiscent frequently postulated iron(V)-oxo-hydroxo (HO–FeV═O) species arene alkene synthetic models. Further, DFT for mechanism HO–MnV═O-mediated reveal first oxo attack step controls enantioselectivity, exhibits high preference over epoxidation. In study, able replicate both function key chemical principles manganese-catalyzed olefins.

Language: Английский

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Manganese(I)-Catalyzed Enantioselective Alkylation To Access P-Stereogenic Phosphines

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 17, 2025

This work introduces a novel Mn(I)-catalyzed enantioselective alkylation methodology that efficiently produces wide array of P-chiral phosphines with outstanding yields and enantioselectivities. Notably, the exceptional reactivity Mn(I) complexes in these reactions is demonstrated by their effective catalysis both typically reactive alkyl iodides bromides, as well less chlorides. approach broadens accessibility to various simplifies synthesis chiral tridentate pincer concise 1–2 step process, contrary conventional, labor-intensive multistep procedures. Importantly, development significantly expands applicability earth-abundant Mn(I)-based beyond recently established roles catalytic hydrogenative conjugate addition reactions, emphasizing potential viable alternative noble metal chemistry and, some cases, even surpassing performance.

Language: Английский

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Fe(II) coordination transition regulates reductive dechlorination: The overlooked abiotic role of lactate

Water Research, Journal Year: 2024, Volume and Issue: 254, P. 121342 - 121342

Published: Feb. 19, 2024

Language: Английский

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Photo‐Induced Generation of Oxygenated Quaternary Centers via EnT Enabled Singlet O₂ Addition to C3‐Maleimidated Quinoxaline: A Reagent‐Less Approach

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(45)

Published: May 8, 2024

Demonstrated here is an external photo-sensitizer-free (auto-sensitized) singlet oxygen-enabled solvent-dependent tertiary hydroxylation and aryl-alkyl spiro-etherification of C3-maleimidated quinoxalines. Such "reagent-less" photo-oxygenation at Csp

Language: Английский

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Manganese Catalyzed Oximation of Hydrocarbons to Oximes

Research Square (Research Square), Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 26, 2025

Oximes are used in many scientific and industrial domains, ranging from organic synthesis through biotechnology to materials science. Traditionally, their necessitates the use of hydrocarbons with specific functional groups, such as carbonyls, which often more challenging expensive obtain compared non-functionalized counterparts. Here we introduce a new approach that enables direct oximes via oxidative oximation methylene C-H bonds — most prevalent molecular unit world molecules. Under catalysis manganese complex hydrogen peroxide oxidant hydroxylamine sulfate amine source, demonstrate diverse array molecules simple chemicals like propane cyclohexane compounds antimalarial drug artemisinin can be oximated at synthetically significant yields under mild conditions. The catalyst displays good level functionality tolerance predictable site selectivity molecule settings. Our opens avenues for oxime is anticipated have broad applications production fine commodity chemicals, bioactive molecules, materials.

Language: Английский

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Nonheme Manganese-Catalyzed Oxidative N-Dealkylation of Tertiary Amides: Manganese(IV)-Oxo Aminopyridine Cation Radical Species and Hydride Transfer Mechanism

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: March 19, 2025

The development of efficient and practical N-dealkylation reactions stands as a longstanding objective in synthetic chemistry. Inspired by the oxidative mediated heme nonheme metalloenzymes, we disclose biomimetic catalysis that utilizes manganese complex bearing anthryl-appended aminopyridine ligand hydrogen peroxide (H2O2) terminal oxidant. A variety Weinreb amides cyclic aliphatic amines are efficiently transformed into valuable methyl hydroxamates ω-amino acids through C-N bond cleavage. Mechanistic studies, including density functional theory (DFT) calculations, reveal manganese(IV)-oxo cation radical species, which is formed via bromoacetic acid-assisted heterolytic O-O cleavage presumed manganese(III)-hydroperoxo species subsequent intramolecular electron transfer (ET) from anthryl group to center, active intermediate initiates reactions; this process reminiscent iron(III)-hydroperoxo porphyrin intermediates (Cpd 0) form iron(IV)-oxo π-cation radicals I) responsible for diverse selective oxidation reactions. Moreover, it revealed activation C-H adjacent nitrogen atom proceeds hydride (HT) mechanism, involves concerted asynchronous proton-coupled (PCET), followed an ET process. Thus, study reports first instance catalytic tertiary amides, such amines, Cpd I-like initial HT pathway.

Language: Английский

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Plasma-enhanced synthesis of nitrogen-doped silicon carbide nanopowders in a fluidized-bed reactor for lithium-ion battery anodes

Chemical Engineering Journal, Journal Year: 2025, Volume and Issue: 514, P. 163086 - 163086

Published: April 25, 2025

Language: Английский

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Debate of Nucleophilic versus Electrophilic Oxidative Aldehyde Deformylation by Mononuclear Nonheme Iron(III)-Peroxo and Iron(IV)-Oxo Complexes

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: April 28, 2025

High-valent iron(IV)-oxo species are fleeting intermediates that perform vital reactions in enzymatic catalysis. In contrast, heme and nonheme iron(III)-peroxo usually act as nucleophiles converted to high-valent iron-oxo for electrophilic oxidation reactions. Herein, we report a study on aldehyde deformylation of 2-phenylpropionaldehyde (2-PPA) its derivatives by complexes bearing tetramethylated cyclam (TMC) analogues, including [FeIII(O2)(12-TMC)]+ (1), [FeIII(O2)(13-TMC)]+ (2), [FeIII(O2)(14-TMC)]+ (3). Reactivity studies employing deuterated substrates, such α-[D1]-2-phenylpropionaldehyde aldehyde-[D]-2-phenylpropionaldehyde, demonstrate 2-PPA the occurs via abstraction stronger C-H atom, rather than expected nucleophilic attack or weaker α-C-H atom Interestingly, preference is retained during complexes, i.e., [FeIV(O)(13-TMC)]2+ (4) [FeIV(O)(N4Py)]2+ (5). DFT calculations reproduce experimental trends reactivity reveal peroxide O-O bond cleaved form an iron(III)-dioxyl conducts abstraction; this chemoselectivity achieved through stabilizing noncovalent interactions between oxidants aromatic ring substrate positions close proximity FeIII-O2/FeIV═O cores. These new theoretical findings together with previous demonstrations ability 1-3 hydrogen transfer, oxygen cis-dihydroxylation highlight cores not inherently can have more important functions chemical biological reactions, acting transient en route metal-oxo intermediates.

Language: Английский

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Asymmetric Epoxidation vs syn-Hydroxy-Acyloxylation of Olefins in the Presence of Sterically Demanding Nonheme Manganese Complexes

ACS Catalysis, Journal Year: 2023, Volume and Issue: 14(1), P. 498 - 507

Published: Dec. 22, 2023

Herewith, we present another facet of the versatile catalytic reactivity bulky bis-amino-bis-pyridylmethyl Mn complexes: besides highly enantioselective (up to 99% ee) epoxidation, benzhydryl-substituted catalysts have been found convert olefinic substrates into products syn-addition C═C bond, hydroxy-carboxylates, that can prevail under certain conditions. The mechanism syn-hydroxy-acyloxylation is discussed, with data obtained providing evidence in favor so far lacking direct OH and OC(O)R transfer from high-valent active species group. Such a conceptually reminiscent Rieske dioxygenases catalyze 1,2-dihydroxylation bonds, simultaneously incorporating two cis-ligands reactive metal center resulting diol syn-selective fashion.

Language: Английский

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