Radical Hydrocarboxylation of Unactivated Alkenes via Photocatalytic Formate Activation

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(20), С. 10991 - 10997

Опубликована: Май 15, 2023

Herein we disclose a strategy to promote the hydrocarboxylation of unactivated alkenes using photochemical activation formate salts. We illustrate that an alternative initiation mechanism circumvents limitations prior approaches and enables this challenging substrate class. Specifically, found accessing requisite thiyl radical initiator without exogenous chromophore eliminates major byproducts have plagued attempts exploit similar reactivity for alkene substrates. This redox-neutral method is technically simple execute effective across broad range Feedstock alkenes, such as ethylene, are hydrocarboxylated at ambient temperature pressure. A series cyclization experiments indicate how described in report can be diverted by more complex processes.

Язык: Английский

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Metallaphotoredox-enabled aminocarboxylation of alkenes with CO2

Nature Catalysis, Год журнала: 2023, Номер 6(10), С. 959 - 968

Опубликована: Сен. 21, 2023

Язык: Английский

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Enantioselective Cyanofunctionalization of Aromatic Alkenes via Radical Anions

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(2), С. 1410 - 1422

Опубликована: Янв. 5, 2024

Alkene radical ions constitute an integral and unique class of reactive intermediates for the synthesis valuable compounds because they have both unpaired spins charge. However, relatively few synthetic applications alkene anions emerged due to a dearth generally applicable mild anion generation approaches. Precise control over chemo- stereoselectivity in anion-mediated processes represents another long-standing challenge their high reactivity. To overcome these issues, here, we develop new redox-neutral strategy that seamlessly merges photoredox copper catalysis enable controlled orthogonal enantioselective cyanofunctionalization via distonic-like species. This enables highly regio-, chemo-, hydrocyanation, deuterocyanation, cyanocarboxylation alkenes without stoichiometric reductants or oxidants under visible light irradiation. protocol provides blueprint exploration transformation potential anions.

Язык: Английский

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Excited Organic Radicals in Photoredox Catalysis

JACS Au, Год журнала: 2025, Номер 5(2), С. 426 - 447

Опубликована: Янв. 29, 2025

Many important synthetic-oriented works have proposed excited organic radicals as photoactive species, yet mechanistic studies raised doubts about whether they can truly function photocatalysts. This skepticism originates from the formation of (photo)redox-active degradation products and picosecond decay electronically radicals, which is considered too short for diffusion-based photoinduced electron transfer reactions. From this perspective, we analyze synthetic transformations where been photocatalysts, comparing their theoretical maximum state potentials with required observed photocatalytic reactivity. We summarize structurally similar photocatalysts indicating different reaction pathways some catalytic systems, addressing cases radical exceed Additionally, perform a kinetic analysis to explain in on subpicosecond time scales. further rationalize potential anti-Kasha reactivity higher states femtosecond lifetimes, highlighting how future photocatalysis advancements could unlock new photochemical pathways.

Язык: Английский

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Visible-light acridinium-based organophotoredox catalysis in late-stage synthetic applications

RSC Advances, Год журнала: 2023, Номер 13(16), С. 10958 - 10986

Опубликована: Янв. 1, 2023

The field of photoredox catalysis has been transformed by the use organic photocatalysts, which give access to re-activities that were previously only possible with transition-metal photocatalysts.

Язык: Английский

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Shining Fresh Light on Complex Photoredox Mechanisms through Isolation of Intermediate Radical Anions

ACS Catalysis, Год журнала: 2023, Номер 13(14), С. 9392 - 9403

Опубликована: Июнь 30, 2023

Photoredox catalysis (PRC) has gained enormous and wide-ranging interest in recent years but also been subject to significant mechanistic uncertainty, even controversy. To provide a method by which the missing understanding can begin be filled in, we demonstrate herein that it is possible isolate as authentic materials one-electron reduction products of representative PRC catalysts (PCs). Specifically, KC8 both 9,10-dicyanoanthracene naphthalene monoamide derivative presence cryptand provides convenient access corresponding [K(crypt)+][PC·-] salts clean fully characterized techniques including EPR XRD. Because PC·- states are key intermediates reactions, such isolation allows for highly controlled study these anions' specific reactivity hence their roles. As demonstration this principle, show used conveniently interrogate mechanisms recent, high-profile "conPET" "e-PRC" currently acute Using very simple experiments, able striking insights into reactions' underlying observe surprising levels hidden complexity would otherwise have challenging identify emphasize care control needed when interrogating interpreting mechanisms. These studies foundation far broader range questions around conPET, e-PRC, other reaction future, using same strategy isolation.

Язык: Английский

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Ketyl Radical Coupling Enabled by Polycyclic Aromatic Hydrocarbon Electrophotocatalysts

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(37), С. 20169 - 20175

Опубликована: Сен. 7, 2023

Herein, we report a new class of electrophotocatalysts, polycyclic aromatic hydrocarbons, that promote the reduction unactivated carbonyl compounds to generate versatile ketyl radical intermediates. This catalytic platform enables previously challenging intermolecular coupling reactions, including those classic reductants (e.g., SmI2/HMPA) have failed promote. More broadly, this study outlines an approach fundamentally expand array reactive intermediates can be generated via electrophotocatalysis by obviating need for rapid mesolytic cleavage following substrate reduction.

Язык: Английский

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Reductive Cleavage of C–X or N–S Bonds Catalyzed by Super Organoreductant CBZ6

Organic Letters, Год журнала: 2023, Номер 25(5), С. 816 - 820

Опубликована: Янв. 24, 2023

The reductive cleavage of C(Ar)-X bonds is the key step for cross coupling Ar-X with other groups. In this work, under irradiation 407 nm LEDs using sodium formate as reductant and thiol hydrogen atom transfer agent, a variety (hetero)aryl chlorides, bromides, iodides could be reduced to corresponding (hetero)arenes. intermediates, aryl radicals, trapped by either hydrogen, phosphite, or borates. same reduction conditions can extended deprotection sulfonamides.

Язык: Английский

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Photocatalytic Reductive Functionalization of Aryl Alkynes via Alkyne Radical Anions

ACS Catalysis, Год журнала: 2024, Номер 14(12), С. 9283 - 9293

Опубликована: Июнь 4, 2024

The direct reductive functionalization of alkynes under mild conditions presents a promising yet challenging avenue for accessing value-added molecules. Alkyne radical anions represent distinct class reactive intermediates characterized by both charge and an unpaired electron, thus holding great potential facilitating diverse bond formations, particularly in alkyne functionalization. However, the synthetic utility is limited, primarily due to difficulty their generation formation highly unstable vinyl intermediates. In this study, we accomplished from aryl feedstocks via single electron transfer (SET) reduction with photogenerated CO2 anion (CO2•–), enabling hydroalkylation, arylalkenylation, hydrocarboxylation alkynes. Our photocatalytic strategy features metal-free catalysis, reaction conditions, employment traceless reductant, good functional group compatibility, step- atom-economy, high regioselectivity. This study not only paves way leveraging underexplored but also catalyzes ongoing exploration bifunctional CO2•– species chemistry.

Язык: Английский

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Metallaphotoredox-catalyzed alkynylcarboxylation of alkenes with CO2 and alkynes for expedient access to β-alkynyl acids

Nature Communications, Год журнала: 2025, Номер 16(1)

Опубликована: Фев. 21, 2025

Carboxylation with CO2 offers an attractive and sustainable access to valuable carboxylic acids. Among these methods, direct C−H carboxylation of terminal alkynes has attracted much attention for one-carbon homologation alkynes, enabling rapid synthesis propiolic In contrast, the multi-carbons construct important non-conjugated alkynyl-containing acids not been reported. Herein, we present alkynylcarboxylation alkenes via photoredox copper dual catalysis. This protocol provides a practical method form alkynyl from readily available CO2. Additionally, this approach also features mild (room temperature, 1 atm CO2) redox-neutral conditions, high atom step economy, good functional group tolerance, selectivities. Moreover, diverse transformations β-alkynyl acid products bioactive molecule (GPR40/FFA1 agonist) further illustrate synthetic utility methodology. The report multi-carbon is rare. authors catalysis, affording

Язык: Английский

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