Photons or Electrons? A Critical Comparison of Electrochemistry and Photoredox Catalysis for Organic Synthesis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2487 - 2649

Опубликована: Ноя. 9, 2021

Redox processes are at the heart of synthetic methods that rely on either electrochemistry or photoredox catalysis, but how do and catalysis compare? Both approaches provide access to high energy intermediates (e.g., radicals) enable bond formations not constrained by rules ionic 2 electron (e) mechanisms. Instead, they 1e mechanisms capable bypassing electronic steric limitations protecting group requirements, thus enabling chemists disconnect molecules in new different ways. However, while providing similar intermediates, differ several physical chemistry principles. Understanding those differences can be key designing transformations forging disconnections. This review aims highlight these similarities between comparing their underlying principles describing impact electrochemical photochemical methods.

Язык: Английский

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Enantioselective Radical Reactions Using Chiral Catalysts

Chemical Reviews, Год журнала: 2022, Номер 122(6), С. 5842 - 5976

Опубликована: Янв. 24, 2022

Benefiting from the impressive increase in fundamental knowledge, last 20 years have shown a continuous burst of new ideas and consequently plethora catalytic methods for enantioselective radical reactions. This review aims to provide complete survey progress achieved over this latter period. The first part focuses on use chiral organocatalysts, these include catalysts covalently linked substrate those that interact with by weaker interactions like hydrogen bonds. second is devoted transition-metal redox catalysis which organized according increasing atomic number first-row transition metals (Ti, Cr, Fe, Mn, Co, Ni, Cu). Bioinspired manganese- iron-mediated hydroxylations oxidations are also discussed. A specific section dedicated reactivity Ru, Rh, Ir complexes as Lewis acids special focus at metal. Absorption photons result different events such energy transfer, single-electron hydrogen-atom transfer facilitating formation radicals. Organocatalysis has been successfully combined photocatalysts, opened pathways enlarging precursors available. merger photocatalysis organo- or metalla-photocatalysis brought novelty allowed discovery large original transformations. enzyme-catalyzed reactions involving intermediates largely benefit visible-light irradiation included review. provides comprehensive inventory goal detailing reaction mechanisms involved transformations any nonspecialist could find their own creativity invent yet unknown applications.

Язык: Английский

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Radical NHC Catalysis

ACS Catalysis, Год журнала: 2022, Номер 12(19), С. 11984 - 11999

Опубликована: Сен. 19, 2022

Radical/radical cross-coupling reactions represent an efficient and straightforward approach for the construction of chemical bonds accordingly have drawn increasing attention over past decades. In order to achieve synthetically useful transformations, a persistent radical should be coupled with transient in accordance effect (PRE). However, known radicals outnumber by far types free radicals, which limits widespread application PRE, until today. Thus, development between has been focus, meanwhile transition-metal catalysis successfully implemented artificially prolong lifetimes, allowing their utilization formal radical/radical cross-couplings. Complementary research field recently uncovered that organocatalytically generated NHC-derived ketyl are type catalytically radicals. NHC-catalyzed transformations aldehydes carboxylic acid derivatives enabled disclosure ever-increasing number interesting reactions, different from traditional ionic processes, offering otherwise inaccessible activation modes. These discoveries opened door NHC organocatalysis manipulation reactions. Due its obvious potential synthetic organic chemistry, it is timely provide perspective on this emerging field.

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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Carbon–sulfur bond formation via photochemical strategies: An efficient method for the synthesis of sulfur-containing compounds

Chinese Chemical Letters, Год журнала: 2021, Номер 33(4), С. 1798 - 1816

Опубликована: Сен. 27, 2021

Язык: Английский

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Aroyl Fluorides as Bifunctional Reagents for Dearomatizing Fluoroaroylation of Benzofurans

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(16), С. 7072 - 7079

Опубликована: Март 22, 2022

The 2,3-dihydrobenzofuran scaffold is widely found in natural products and biologically active compounds. Herein, dearomatizing 2,3-fluoroaroylation of benzofurans with aroyl fluorides as bifunctional reagents to access 2,3-difunctionalized dihydrobenzofurans reported. reaction that occurs by cooperative NHC/photoredox catalysis provides 3-aroyl-2-fluoro-2,3-dihydrobenzofurans moderate good yield high diastereoselectivity. Cascades proceed via radical/radical cross-coupling a benzofuran radical cation generated the photoredox cycle neutral ketyl formed through NHC cycle. redox-neutral transformation exhibits broad substrate scope functional group compatibility. With anhydrides reagents, aroyloxyacylation achieved strategy can also be applied

Язык: Английский

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Switchable Divergent Synthesis Using Photocatalysis

ACS Catalysis, Год журнала: 2022, Номер 12(3), С. 1857 - 1878

Опубликована: Янв. 20, 2022

A highly selective and divergent synthesis enables access to various molecules has garnered broad interest from not only organic chemists but also medicinal biologists who work with chemical libraries. Since the 20th century, such transformations have been achieved using transition-metal-catalyzed reactions, in which choice of catalyst or ligand crucially affects selectivity. Over past several decades, photocatalysts attracted a considerable amount attention because they provide additional ways control reaction intermediates product selectivity via electron energy transfer. From this perspective, we highlight recent development switchable syntheses photocatalysts, are difficult achieve classical catalytic transformations.

Язык: Английский

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Ferrocene-Mediated Photocatalytic Annulation of N-Sulfonyl Ketimines on a Polycrystalline WSe₂ Semiconductor Photocatalyst

ACS Catalysis, Год журнала: 2023, Номер 13(19), С. 13071 - 13076

Опубликована: Сен. 22, 2023

A merger of heterogeneous polycrystalline WSe2 semiconductor photocatalysis and homogeneous ferrocene redox catalysis for the cascade radical coupling-annulation reactions was established. In redox-mediated photocatalysis, can improve separation photogenerated hole–electron pairs on by consuming hole via formation a cation, which triggered molecular transformations. Various benzo[e]imidazo[1,5-c][1,2,3]oxathiazine 5,5-dioxides were formed through semiheterogeneous three-component reaction N-sulfonyl ketimines, N-arylglycines, formaldehyde.

Язык: Английский

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Semi-heterogeneous g-C₃N₄/NaI dual catalytic C–C bond formation under visible light

Green Chemistry, Год журнала: 2023, Номер 25(8), С. 3292 - 3296

Опубликована: Янв. 1, 2023

The semi-heterogeneous g-C 3 N 4 /NaI dual catalytic system driven C–C bond formation between quinoxalin-2(1 H )-ones and arylhydrazines under blue light irradiation is reported for the first time.

Язык: Английский

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Sulfonium Salts as Acceptors in Electron Donor‐Acceptor Complexes

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(29)

Опубликована: Март 24, 2023

Abstract The photoactivation of electron donor‐acceptor complexes has emerged as a sustainable, selective and versatile strategy for the generation radical species. Electron (EDA) complexation, however, imposes electronic constraints on donor acceptor components this can limit range radicals that be generated using approach. New EDA complexation strategies exploiting sulfonium salts allow to from native functionality. For example, aryl salts, formed by activation arenes, serve in due their electron‐deficient nature. This “sulfonium tag” approach relaxes parent substrate dramatically expands complexation. In review, these new applications will introduced areas chemical space rendered accessible through innovation highlighted.

Язык: Английский

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