Heterogeneous Photocatalytic Strategies for C(sp³)−H Activation

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(13)

Опубликована: Янв. 16, 2024

Abstract Activation of ubiquitous C(sp 3 )−H bonds is extremely attractive but remains a great challenge. Heterogeneous photocatalysis offers promising and sustainable approach for activation has been fast developing in the past decade. This Minireview focuses on mechanism strategies heterogeneous photocatalytic activation. After introducing mechanistic insights, including precise design active sites, regulation reactive radical species, improving charge separation reactor innovations are discussed. In addition, recent advances hydrocarbons, alcohols, ethers, amines amides by summarized. Lastly, challenges opportunities outlined to encourage more efforts development this exciting field.

Язык: Английский

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Direct 1,2‐Dicarbonylation of Alkenes towards 1,4‐Diketones via Photocatalysis

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(51), С. 26822 - 26828

Опубликована: Сен. 29, 2021

1,4-Dicarbonyl compounds are intriguing motifs and versatile precursors in numerous pharmaceutical molecules bioactive natural compounds. Direct incorporation of two carbonyl groups into a double bond at both ends is straightforward, but also challenging. Represented herein the first example 1,2-dicarbonylation alkenes by photocatalysis. Key to success that N(n-Bu)4+ not only associates with alkyl anion avoid protonation, activates α-keto acid undergo electrophilic addition. The employed for acyl generation By tuning reductive ability precursor, unsymmetric 1,4-dicarbonylation achieved time. This metal-free, redox-neutral regioselective executed photocatalyst substrates under extremely mild conditions shows great potential biomolecular drug molecular derivatization.

Язык: Английский

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Direct, Site‐Selective and Redox‐Neutral α‐C−H Bond Functionalization of Tetrahydrofurans via Quantum Dots Photocatalysis

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(52), С. 27201 - 27205

Опубликована: Сен. 18, 2021

As one of the most ubiquitous bulk reagents available, intrinsic chemical inertness tetrahydrofuran (THF) makes direct and site-selective C(sp3 )-H bond activation difficult, especially under redox neutral condition. Here, we demonstrate that semiconductor quantum dots (QDs) can activate α-C-H THF via forming QDs/THF conjugates. Under visible light irradiation, resultant alkoxyalkyl radical directly engages in cross-coupling with α-amino from amino C-H bonds or addition alkene phenylacetylene, respectively. In contrast to stoichiometric oxidant hydrogen atom transfer required previous studies, scalable benchtop approach execute only by a QD photocatalyst redox-neutral condition, thus providing broad value added chemicals starting THFs reagent.

Язык: Английский

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Direct N−H Activation to Generate Nitrogen Radical for Arylamine Synthesis via Quantum Dots Photocatalysis

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(17)

Опубликована: Фев. 21, 2023

Represented herein is the first example of N-radical generation direct from N-H bond activation under mild and redox-neutral conditions. The in situ generated intercepts a reduced heteroarylnitrile/aryl halide for C-N formation visible-light irradiation quantum dots (QDs). A series aryl alkylamines with heteroarylnitriles/aryl halides exhibit high efficiency, site-selectivity good functional-group tolerance. Moreover, consecutive C-C using benzylamines as substrates also achieved, producing N-aryl-1,2-diamines H2 evolution. conditions, broad substrate scope, efficiency are advantageous organic synthesis.

Язык: Английский

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Electrochemical Gelation of Metal Chalcogenide Quantum Dots: Applications in Gas Sensing and Photocatalysis

Accounts of Chemical Research, Год журнала: 2023, Номер 56(9), С. 1087 - 1096

Опубликована: Апрель 20, 2023

ConspectusMetal chalcogenide quantum dots (QDs) are prized for their unique and functional properties, associated with both intrinsic (quantum confinement) extrinsic (high surface area) effects, as dictated by size, shape, characteristics. Thus, they have considerable promise diverse applications, including energy conversion (thermoelectrics photovoltaics), photocatalysis, sensing. QD gels macroscopic porous structures consisting of interconnected QDs pore networks in which the pores may be filled solvent (i.e., wet gels) or air aerogels). because can prepared macroscale objects while fully retaining size-specific quantum-confined properties initial building blocks. The extensive porosity also ensures that each gel network is accessible to ambient, leading high performance applications require areas, such (photo)catalysis sensing.Metal conventionally chemical approaches. We recently expanded toolbox synthesis developing electrochemical gelation methods. Relative conventional oxidation approaches, assembly (1) enables use two additional levers tuning process structure: electrode material potential, (2) allows direct formation on device substrates simplify fabrication improve reproducibility. discovered distinct methods, writing an active free-standing monoliths. Oxidative electrogelation leads assemblies bridged dichalcogenide (covalent) linkers, whereas metal-mediated proceeds via electrodissolution metal electrodes produce free ions link binding pendant carboxylate functionalities ligands (non-covalent linkers). further demonstrated electrogel composition produced from covalent could modified controlled ion exchange form single-ion decorated bimetallic gels, a new category materials. exhibit unprecedented NO2 gas sensing photocatalytic reactivities (e.g., "cyano dance" isomerization reductive ring-opening arylation). chemistry unveiled during development pathways post-modification has broad implications guiding design nanoparticle strategies gel-based sensors catalysts.

Язык: Английский

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α‐Acylation of Alkenes by a Single Photocatalyst

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(52)

Опубликована: Окт. 7, 2022

A direct strategy for the difunctionalization of alkenes, with acylation occurring at more substituted alkene position, would be attractive complex ketone synthesis. We report herein a reaction driven by single photocatalyst that enables α-acylation in this way introduction fluoromethyl, alkyl, sulfonyl or thioether group β-position high chemo- and regioselectivity under extremely mild conditions. Crucial to success method are rate differences kinetics radical generation through single-electron transfer (SET) between different precursors excited (PC*). Thus, is first occupied derived from precursor can generated most readily, α-keto acids could used as an electrophilic reagent alkenes.

Язык: Английский

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Direct Excitation of Aldehyde to Activate the C(sp²)−H Bond by Cobaloxime Catalysis toward Fluorenones Synthesis with Hydrogen Evolution

Angewandte Chemie International Edition, Год журнала: 2022, Номер 62(7)

Опубликована: Дек. 13, 2022

A new way to form fluorenones via the direct excitation of substrates instead photocatalyst activate C(sp2 )-H bond under redox-neutral condition is reported. Our design relies on photoexcited aromatic aldehyde intermediates that can be intercepted by cobaloxime catalyst through single electron transfer for following β-H elimination. The generation acyl radical and successful interception a metal avoid use stoichiometric external oxidants, affording series highly substituted fluorenones, including six-membered ketones, such as xanthone thioxanthone derivatives in good excellent yields, with hydrogen only byproduct. This catalytic system features readily available catalyst, mild reaction conditions broad substrate scope, which sunlight scale-up experiments continuous-flow approach make methodology sustainable amenable potentially operational procedures.

Язык: Английский

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Recent Progress in C–S Bond Formation via Electron Donor-Acceptor Photoactivation

Organic & Biomolecular Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

This review summarizes recent progress in EDA complex-promoted C–S bond formation using various sulfur-containing substrates under mild conditions via visible light irradiation.

Язык: Английский

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Direct 1,2‐Dicarbonylation of Alkenes towards 1,4‐Diketones via Photocatalysis

Angewandte Chemie, Год журнала: 2021, Номер 133(51), С. 27026 - 27032

Опубликована: Сен. 29, 2021

Abstract 1,4‐Dicarbonyl compounds are intriguing motifs and versatile precursors in numerous pharmaceutical molecules bioactive natural compounds. Direct incorporation of two carbonyl groups into a double bond at both ends is straightforward, but also challenging. Represented herein the first example 1,2‐dicarbonylation alkenes by photocatalysis. Key to success that N( n ‐Bu) 4 + not only associates with alkyl anion avoid protonation, activates α‐keto acid undergo electrophilic addition. The employed for acyl generation By tuning reductive ability precursor, unsymmetric 1,4‐dicarbonylation achieved time. This metal‐free, redox‐neutral regioselective executed photocatalyst substrates under extremely mild conditions shows great potential biomolecular drug molecular derivatization.

Язык: Английский

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Direct, Site‐Selective and Redox‐Neutral α‐C−H Bond Functionalization of Tetrahydrofurans via Quantum Dots Photocatalysis

Angewandte Chemie, Год журнала: 2021, Номер 133(52), С. 27407 - 27411

Опубликована: Сен. 18, 2021

Abstract As one of the most ubiquitous bulk reagents available, intrinsic chemical inertness tetrahydrofuran (THF) makes direct and site‐selective C(sp 3 )−H bond activation difficult, especially under redox neutral condition. Here, we demonstrate that semiconductor quantum dots (QDs) can activate α‐C−H THF via forming QDs/THF conjugates. Under visible light irradiation, resultant alkoxyalkyl radical directly engages in cross‐coupling with α‐amino from amino C−H bonds or addition alkene phenylacetylene, respectively. In contrast to stoichiometric oxidant hydrogen atom transfer required previous studies, scalable benchtop approach execute only by a QD photocatalyst redox‐neutral condition, thus providing broad value added chemicals starting THFs reagent.

Язык: Английский

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