Photocatalytic Late-Stage C–H Functionalization

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(8), P. 4237 - 4352

Published: Jan. 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.

Language: Английский

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Sustainable Thioetherification via Electron Donor–Acceptor Photoactivation Using Thianthrenium Salts

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(22)

Published: March 16, 2022

Abstract The synthesis of sulfides has been widely studied because this functional subunit is prevalent in biomolecules and pharmaceuticals, as well being a useful synthetic platform for further elaboration. Thus, various methods to build C−S bonds have developed, but typically they require the use precious metals or harsh conditions. Electron donor–acceptor (EDA) complex photoactivation strategies emerged versatile sustainable ways achieve bond formation, avoiding challenges associated with previous methods. This work describes an open‐to‐air, photoinduced, site‐selective C−H thioetherification from readily available reagents via EDA formation that tolerates wide range different groups. Moreover, C(sp 2 )−halogen remain intact using protocol, allowing late‐stage installation sulfide motif bioactive scaffolds, while yet modification through more traditional C−X cleavage protocols. Additionally, mechanistic investigations support envisioned scenario.

Language: Английский

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Recent Advances in Employing Catalytic Donors and Acceptors in Electron Donor–Acceptor Complex Photochemistry

The Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 87(16), P. 10555 - 10563

Published: July 29, 2022

Electron donor–acceptor (EDA) complexes provide a means to initiate radical reactions under visible light irradiation using substrates that do not absorb individually. Catalytic approaches complex formation are vital for advancing this synthetic strategy as it decouples the complexation and photogeneration of radicals from substrate functionalization, limitation inherent stoichiometric restricts structural diversity. This Synopsis highlights recent developments in EDA photochemistry which either donor or acceptor employed catalytically.

Language: Английский

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EDA photochemistry: Mechanistic investigations and future opportunities

Chem, Journal Year: 2023, Volume and Issue: 9(9), P. 2390 - 2415

Published: July 18, 2023

Language: Английский

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Tetrachlorophthalimides as Organocatalytic Acceptors for Electron Donor–Acceptor Complex Photoactivation

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(20), P. 8914 - 8919

Published: May 13, 2022

Excitation of photoactive electron donor-acceptor (EDA) complexes is an effective way to generate radicals. Applications in a catalytic regime typically use donors. Herein, we report that readily available electron-poor tetrachlorophthalimides can act as organocatalytic acceptors trigger the formation EDA with variety radical precursors not amenable previous methods. visible light generates carbon radicals under mild conditions. The versatility this complex platform allowed us develop mechanistically distinct reactions, including combination cobalt-based system. Quantum yield measurements established closed cycle operational, which hints at ability turn over and govern each cycle.

Language: Английский

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Recent Advances in Electron Donor‐Acceptor (EDA)‐Complex Reactions involving Quaternary Pyridinium Derivatives

Advanced Synthesis & Catalysis, Journal Year: 2023, Volume and Issue: 365(10), P. 1538 - 1564

Published: March 6, 2023

Abstract Quaternary pyridinium compounds are valuable intermediates in organic synthesis, which have gained immense popularity the synthetic community. The application of transition metal or photoredox catalysis transforming quaternary into various C−C and C−X bonds is well established. A majority these methods require high temperatures, expansive catalysts, delicate conditions for successful execution. On other hand, use metal‐free photocatalysis‐free strategies constructing using derivatives has been sought‐after. In this context, electron‐donor‐acceptor (EDA)‐complex reactions emerged as a state‐of‐the‐art methodology, do not any photocatalyst their EDA‐complex photochemistry takes advantage electron‐acceptor ability derivatives, can quickly generate radical precursor via deaminative process. These newly generated useful several transformations. We hereby, review, discuss an area major progress mediated involving with mechanism, substrate scope, limitations. magnified image

Language: Английский

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Characterization of A π–π stacking cocrystal of 4-nitrophthalonitrile directed toward application in photocatalysis

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Feb. 16, 2024

Abstract Photoexcitation of the electron-donor-acceptor complexes have been an effective approach to achieve radicals by triggering electron transfer. However, catalytic version complex photoactivation is quite underdeveloped comparing well-established utilization electronically biased partners. In this work, we utilize 4-nitrophthalonitrile as acceptor facilitate efficient π-stacking with electron-rich aromatics form complex. The characterization and energy profiles on cocrystal 1,3,5-trimethoxybenzene disclose that transfer highly favorable under light irradiation. This catalyst can be efficiently applied in benzylic C−H bond developing Giese reaction alkylanisoles oxidation benzyl alcohols. A broad scope tolerated a mechanism also proposed. Moreover, corresponding π-anion interaction potassium formate further hydrocarboxylation alkenes efficiently.

Language: Английский

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Ni/Photoredox-Catalyzed C(sp³)–C(sp³) Coupling between Aziridines and Acetals as Alcohol-Derived Alkyl Radical Precursors

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(43), P. 20067 - 20077

Published: Oct. 18, 2022

Aziridines are readily available C(sp3) precursors that afford valuable β-functionalized amines upon ring opening. In this article, we report a Ni/photoredox methodology for C(sp3)-C(sp3) cross-coupling between aziridines and methyl/1°/2° aliphatic alcohols activated as benzaldehyde dialkyl acetals. Orthogonal activation modes of each alkyl coupling partner facilitate cross-selectivity in the bond-forming reaction: acetal is via hydrogen atom abstraction β-scission bromine radical (generated situ from single-electron oxidation bromide), whereas aziridine at Ni center reduction. We demonstrate an Ni(II) azametallacycle, conventionally proposed cross-coupling, not intermediate productive cross-coupling. Rather, stoichiometric organometallic linear free energy relationship studies indicate proceeds Ni(I) oxidative addition, previously unexplored elementary step.

Language: Английский

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Photochemical Organocatalytic Functionalization of Pyridines via Pyridinyl Radicals

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 145(1), P. 47 - 52

Published: Dec. 27, 2022

We report a photochemical method for the functionalization of pyridines with radicals derived from allylic C–H bonds. Overall, two substrates undergo to form new C(sp2)–C(sp3) bond. The chemistry harnesses unique reactivity pyridinyl radicals, generated upon single-electron reduction pyridinium ions, which effective coupling radicals. This novel mechanism enables distinct positional selectivity pyridine that diverges classical Minisci chemistry. Crucial was identification dithiophosphoric acid masters three catalytic tasks, sequentially acting as Brønsted protonation, single electron transfer (SET) reductant ion reduction, and hydrogen atom abstractor activation C(sp3)–H resulting then couple high regioselectivity.

Language: Английский

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Synthesis of 1-perfluoroalkyl-3-heteroaryl bicyclo[1.1.1]pentanes via visible light-induced and metal-free perfluoroalkylation of [1.1.1]propellane

Green Chemistry, Journal Year: 2023, Volume and Issue: 25(5), P. 1948 - 1954

Published: Jan. 1, 2023

Visible light-induced perfluoroalkylation of [1.1.1]propellane provides a sustainable way to incorporate perfluoroalkyl-substituted BCPs into various heterocycles.

Language: Английский

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