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

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 2487 - 2649

Published: Nov. 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.

Language: Английский

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Multi‐Photon Excitation in Photoredox Catalysis: Concepts, Applications, Methods

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(26), P. 10266 - 10284

Published: Jan. 16, 2020

Abstract The energy of visible photons and the accessible redox potentials common photocatalysts set thermodynamic limits to photochemical reactions that can be driven by traditional visible‐light irradiation. UV excitation damaging induce side reactions, hence or even near‐IR light is usually preferable. Thus, photochemistry currently faces two divergent challenges, namely desire perform ever more thermodynamically demanding with increasingly lower photon energies. pooling low‐energy address both challenges simultaneously, whilst multi‐photon spectroscopy well established, synthetic photoredox chemistry has only recently started exploit processes on preparative scale. Herein, we have a critical look at developed mechanistic concepts, discuss pertinent experimental methods, provide an outlook into possible future developments this rapidly emerging area.

Language: Английский

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Photocatalysis in the Life Science Industry

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 2907 - 2980

Published: Sept. 24, 2021

In the pursuit of new pharmaceuticals and agrochemicals, chemists in life science industry require access to mild robust synthetic methodologies systematically modify chemical structures, explore novel space, enable efficient synthesis. this context, photocatalysis has emerged as a powerful technology for synthesis complex often highly functionalized molecules. This Review aims summarize published contributions field from industry, including research industrial-academic partnerships. An overview developed strategic applications synthesis, peptide functionalization, isotope labeling, both DNA-encoded traditional library is provided, along with summary state-of-the-art photoreactor effective upscaling photocatalytic reactions.

Language: Английский

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Sequential C–F bond functionalizations of trifluoroacetamides and acetates via spin-center shifts

Science, Journal Year: 2021, Volume and Issue: 371(6535), P. 1232 - 1240

Published: March 5, 2021

Defluorinative functionalization of readily accessible trifluoromethyl groups constitutes an economical route to partially fluorinated molecules. However, the controllable replacement one or two fluorine atoms while maintaining high chemoselectivity remains a formidable challenge. Here we describe general strategy for sequential carbon-fluorine (C-F) bond functionalizations trifluoroacetamides and trifluoroacetates. The reaction begins with activation carbonyl oxygen atom by 4-dimethylaminopyridine-boryl radical, followed spin-center shift trigger C-F scission. A chemoselectivity-controllable two-stage process enables generation difluoro- monofluoroalkyl radicals, which are selectively functionalized different radical traps afford diverse products. mechanism origin were established experimental computational approaches.

Language: Английский

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Visible-Light-Driven Reductive Carboarylation of Styrenes with CO₂ and Aryl Halides

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(18), P. 8122 - 8129

Published: April 20, 2020

The first example of visible-light-driven reductive carboarylation styrenes with CO2 and aryl halides in a regioselective manner has been achieved. A broad range iodides bromides were compatible this reaction. Moreover, pyridyl halides, alkyl even chlorides also viable method. These findings may stimulate the exploration novel Meerwein arylation-addition reactions user-friendly as radical sources photocatalytic utilization CO2.

Language: Английский

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Radical Chain Reduction via Carbon Dioxide Radical Anion (CO₂^•–)

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(24), P. 8987 - 8992

Published: June 9, 2021

We developed an effective method for reductive radical formation that utilizes the anion of carbon dioxide (CO2•–) as a powerful single electron reductant. Through polarity matched hydrogen atom transfer (HAT) between electrophilic and formate salt, CO2•– occurs key element in new chain reaction. Here, initiation can be performed through photochemical or thermal means, we illustrate ability this approach to accomplish activation range substrate classes. Specifically, employed strategy intermolecular hydroarylation unactivated alkenes with (hetero)aryl chlorides/bromides, deamination arylammonium salts, aliphatic ketyl formation, sulfonamide cleavage. show reactivity electron-poor olefins results either reduction alkene hydrocarboxylation, where potentials utilized predict reaction outcome.

Language: Английский

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Organophotoredox Hydrodefluorination of Trifluoromethylarenes with Translational Applicability to Drug Discovery

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(20), P. 9181 - 9187

Published: May 7, 2020

Molecular editing such as insertion, deletion, and single atom exchange in highly functionalized compounds is an aspirational goal for all chemists. Here, we disclose a photoredox protocol the replacement of fluorine with hydrogen electron-deficient trifluoromethylarenes including complex drug molecules. A robustness screening experiment shows that this reductive defluorination tolerates range functional groups heterocycles commonly found bioactive Preliminary studies allude to catalytic cycle whereby excited state organophotocatalyst reductively quenched by donor, returned its original oxidation trifluoromethylarene.

Language: Английский

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Reticular Synthesis of tbo Topology Covalent Organic Frameworks

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(38), P. 16346 - 16356

Published: Aug. 25, 2020

The metal–organic framework (MOF) HKUST-1 with a tbo topology serves as an archetypal tunable and isoreticular platform for targeting desired applications, but the design synthesis of tbo-covalent organic frameworks (COFs) remains formidable challenge. Here we demonstrate successful use reticular chemistry appropriate strategy deliberate construction COFs topology. judicious selection perquisite planar building blocks, 4-connected square tetramine porphyrin 3-connected trigonal trialdehydes triphenylamine, allows condensation two tbo-COFs, first examples resulting both crystallize in cubic Pm3̅ space group adopt non-interpenetrated open framework, which each tritopic linker connects to three units forming truncated Td-octahedron occupies alternating triangular faces octahedron. Owing presence different types photoredox-active moieties, can be efficient heterogeneous photocatalysts oxidative hydroxylation arylboronic acids reductive defluoroalkylation trifluoromethyl aromatics alkenes. present finding will provide impetus examine potential tbo-COFs new engineering multifunctional materials via expansion functionalization blocks.

Language: Английский

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Recent advance in the C–F bond functionalization of trifluoromethyl-containing compounds

Organic Chemistry Frontiers, Journal Year: 2021, Volume and Issue: 8(14), P. 3915 - 3942

Published: Jan. 1, 2021

The C–F bond is the strongest single in organic compounds.

Language: Английский

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Frustrated Lewis-Pair-Meditated Selective Single Fluoride Substitution in Trifluoromethyl Groups

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(5), P. 2572 - 2578

Published: Jan. 14, 2020

Single fluoride substitution in trifluoromethylarenes is an ongoing synthetic challenge that often leads to "over-reaction", where multiple fluorides are replaced. Development of this reaction would allow simple access a vast range difluoromethyl derivatives current interest pharmaceutical, agrochemistry, and materials sciences. Using catalytic frustrated Lewis pair approach, we have developed generic protocol allows single one trifluoromethyl groups with neutral phosphine pyridine bases. The resulting phosphonium pyridinium salts can be further functionalized via nucleophilic substitution, photoredox coupling, electrophilic transfer reactions allowing the generation array products.

Language: Английский

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