Direct Photocatalyzed Hydrogen Atom Transfer (HAT) for Aliphatic C–H Bonds Elaboration

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 1875 - 1924

Опубликована: Авг. 6, 2021

Direct photocatalyzed hydrogen atom transfer (d-HAT) can be considered a method of choice for the elaboration aliphatic C–H bonds. In this manifold, photocatalyst (PCHAT) exploits energy photon to trigger homolytic cleavage such bonds in organic compounds. Selective bond may achieved by judicious abstractor (key parameters are electronic character and molecular structure), as well reaction additives. Different classes PCsHAT available, including aromatic ketones, xanthene dyes (Eosin Y), polyoxometalates, uranyl salts, metal-oxo porphyrin tris(amino)cyclopropenium radical dication. The processes (mainly C–C formation) most cases carried out under mild conditions with help visible light. aim review is offer comprehensive survey synthetic applications d-HAT.

Язык: Английский

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Photocatalytic Late-Stage C–H Functionalization

Chemical Reviews, Год журнала: 2023, Номер 123(8), С. 4237 - 4352

Опубликована: Янв. 24, 2023

The emergence of modern photocatalysis, characterized by mildness and selectivity, has significantly spurred innovative late-stage C–H functionalization approaches that make use low energy photons as a controllable source. Compared to traditional strategies, photocatalysis paves the way toward complementary and/or previously unattainable regio- chemoselectivities. Merging compelling benefits with workflow offers potentially unmatched arsenal tackle drug development campaigns beyond. This Review highlights photocatalytic strategies small-molecule drugs, agrochemicals, natural products, classified according targeted bond newly formed one. Emphasis is devoted identifying, describing, comparing main mechanistic scenarios. draws critical comparison between established ionic chemistry photocatalyzed radical-based manifolds. aims establish current state-of-the-art illustrate key unsolved challenges be addressed in future. authors aim introduce general readership functionalization, specialist practitioners evaluation methodologies, potential for improvement, future uncharted directions.

Язык: Английский

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Catalytic three-component dicarbofunctionalization reactions involving radical capture by nickel

Chemical Society Reviews, Год журнала: 2021, Номер 50(19), С. 10836 - 10856

Опубликована: Янв. 1, 2021

The catalytic dicarbofunctionalization of unsaturated π bonds represents a powerful platform for the rapid construction complex motifs. Despite remarkable progress, novel and efficient methods achieving such transformations under milder conditions with chemo-, regio-, stereoselectivity still remain significant challenge; thus, their development is highly desirable. Recently, merging nickel catalysis radical chemistry offers new benign unprecedented reactivity selectivity. In this review, we summarize recent advances in area by underpinning domino involving capture to provide clear overview reaction designs mechanistic scenarios.

Язык: Английский

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Multicomponent reactions and photo/electrochemistry join forces: atom economy meets energy efficiency

Chemical Society Reviews, Год журнала: 2022, Номер 51(6), С. 2313 - 2382

Опубликована: Янв. 1, 2022

Visible-light photoredox catalysis has been regarded as an extremely powerful tool in organic chemistry, bringing the spotlight back to radical processes. The versatility of photocatalyzed reactions already demonstrated be effective providing alternative routes for cross-coupling well multicomponent reactions. photocatalyst allows generation high-energy intermediates through light irradiation rather than using highly reactive reagents or harsh reaction conditions. In a similar vein, electrochemistry experienced fruitful renaissance generating without need any catalyst. Such milder approaches pose basis toward higher selectivity and broader applicability. electrochemical reactions, species acts starter cascade events. This diverse reactivity use is usually not covered by classical methods. Owing availability cheaper more standardized photo- reactors, easily scalable flow-setups, it surprising that these two fields have become areas increased research interest. Keeping view, this review aimed at overview synthetic design MCRs involving and/or activation crucial step with particular focus on choice difunctionalized reagent.

Язык: Английский

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Photochemical C–H Activation Enables Nickel-Catalyzed Olefin Dicarbofunctionalization

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(10), С. 3901 - 3910

Опубликована: Март 4, 2021

Alkenes, ethers, and alcohols account for a significant percentage of bulk reagents available to the chemistry community. The petrochemical, pharmaceutical, agrochemical industries each consume gigagrams these materials as fuels solvents year. However, utilization such building blocks construction complex small molecules is limited by necessity prefunctionalization achieve chemoselective reactivity. Herein, we report implementation efficient, sustainable, diaryl ketone hydrogen-atom transfer (HAT) catalysis activate native C–H bonds multicomponent dicarbofunctionalization alkenes. ability forge new carbon–carbon between typically viewed commodity provides new, more atom-economic outlook organic synthesis. Through detailed experimental computational investigation, critical effect hydrogen bonding on reactivity this transformation was uncovered.

Язык: Английский

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Ni-Catalyzed Ligand-Controlled Regiodivergent Reductive Dicarbofunctionalization of Alkenes

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(27), С. 10282 - 10291

Опубликована: Июнь 24, 2021

Transition-metal-catalyzed dicarbofunctionalization of alkenes involving intramolecular Heck cyclization followed by intermolecular cross-coupling has emerged as a powerful engine for building heterocycles with sterically congested quaternary carbon centers. However, only exo-cyclization/cross-coupling products can be obtained; endo-selective cyclization/cross-coupling not been reported yet and still poses formidable challenge. We herein report the first example catalyst-controlled regiodivergent synthesis five- six-membered benzo-fused lactams bearing all-carbon Using chiral Pyrox- or Phox-type bidentate ligand, 5-exo cyclization/cross-couplings proceed favorably to produce indole-2-ones in good yields excellent regioselectivity enantioselectivities (up 98% ee). When C6-carboxylic acid-modified 2,2′-bipyridine was used 3,4-dihydroquinolin-2-ones were obtained through 6-endo-selective processes. This transformation is modular tolerant variety functional groups. The ligand rather than substrate structures precisely dictates pattern. Moreover, synthetic value this protocol demonstrated preparation biologically relevant molecules structural scaffolds.

Язык: Английский

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Metallaphotoredox catalysis for sp³C–H functionalizations through hydrogen atom transfer (HAT)

Chemical Society Reviews, Год журнала: 2023, Номер 52(12), С. 4099 - 4120

Опубликована: Янв. 1, 2023

sp 3 C–H functionalizations under the combination of photocatalytic HAT and transition metal catalysis.

Язык: Английский

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Resurgence and advancement of photochemical hydrogen atom transfer processes in selective alkane functionalizations

Chemical Science, Год журнала: 2023, Номер 14(25), С. 6841 - 6859

Опубликована: Янв. 1, 2023

The selective functionalization of alkanes has long been recognized as a prominent challenge and an arduous task in organic synthesis. Hydrogen atom transfer (HAT) processes enable the direct generation reactive alkyl radicals from feedstock have successfully employed industrial applications such methane chlorination process,

Язык: Английский

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Dual Nickel/Photoredox-Catalyzed Asymmetric Carbosulfonylation of Alkenes

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(23), С. 12532 - 12540

Опубликована: Май 30, 2023

An asymmetric three-component carbosulfonylation of alkenes is presented here. The reaction, involving the simultaneous formation a C-C and C-S bond across π-system, uses dual nickel/photoredox catalytic system to produce both β-aryl β-alkenyl sulfones in high yields with excellent levels stereocontrol (up 99:1 er). This protocol exhibits broad substrate scope functional group tolerance its synthetic potential has been demonstrated by successful applications toward pharmacologically relevant molecules. A array control experiments supports involvement secondary alkyl radical intermediate generated through addition sulfonyl double bond. Moreover, stoichiometric cross-over further suggest an underlying Ni(0)/Ni(I)/Ni(III) pathway operative these transformations.

Язык: Английский

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Nickel-catalysed enantioselective alkene dicarbofunctionalization enabled by photochemical aliphatic C–H bond activation

Nature Catalysis, Год журнала: 2024, Номер 7(6), С. 655 - 665

Опубликована: Апрель 29, 2024

Abstract The development of novel strategies to rapidly construct complex chiral molecules from readily available feedstocks is a long-term pursuit in the chemistry community. Radical-mediated alkene difunctionalizations represent an excellent platform towards this goal. However, asymmetric versions remain highly challenging, and more importantly, examples featuring simple hydrocarbons as reaction partners are elusive. Here we report three-component dicarbofunctionalization capitalizing on direct activation C( sp 3 )–H bonds through combination photocatalysed hydrogen atom transfer nickel catalysis. This protocol provides efficient for installing two vicinal carbon–carbon across alkenes atom-economic fashion, providing wide array high-value α-aryl/alkenyl carbonyls phosphonates, well 1,1-diarylalkanes ubiquitous alkane, ether alcohol feedstocks. method exhibits operational simplicity, broad substrate scope regioselectivity, chemoselectivity enantioselectivity. compatibility with bioactive motifs expedient synthesis pharmaceutically relevant highlight synthetic potential protocol.

Язык: Английский

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