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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Hantzsch esters: an emerging versatile class of reagents in photoredox catalyzed organic synthesis

Organic & Biomolecular Chemistry, Journal Year: 2019, Volume and Issue: 17(29), P. 6936 - 6951

Published: Jan. 1, 2019

This minireview highlights the recent advances in chemistry of Hantzsch esters photoredox catalyzed organic synthesis, with particular emphasis placed on reaction mechanisms.

Language: Английский

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Catalytic Intermolecular Dicarbofunctionalization of Styrenes with CO₂ and Radical Precursors

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 56(36), P. 10915 - 10919

Published: July 12, 2017

A redox-neutral intermolecular dicarbofunctionalization of styrenes with CO2 at atmospheric pressure and carbon-centered radicals is described. This mild protocol results in multiple C-C bond-forming reactions from simple precursors the absence stoichiometric reductants, thus exploiting a previously unrecognized opportunity that complements existing catalytic carboxylation events.

Language: Английский

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Radical Fluoroalkylation Reactions

ACS Catalysis, Journal Year: 2018, Volume and Issue: 8(8), P. 7287 - 7307

Published: June 25, 2018

Recent protocols and reactions for catalytic radical perfluoroalkylations will be described. The production of perfluoroalkyl radicals (RF = CnF2n+1, n ≥ 2), which effect both addition substitution on organic substrates, can realized through a range diverse methods such as the well-established visible-light transition-metal-mediated photocatalysis, organic-dye-photocatalyzed reactions, electron donor–acceptor complexes, more recently frustrated Lewis pairs. Thus, perfluoroalkylation carbon–carbon multiple bonds, isocyanides, nitrones, hydrazones, β-keto esters, α-cyano arylacetates, sulfides, (hetero)arenes Special emphasis placed examples published after 2015, where higher fluorinated series fluoroalkylating reagents are studied.

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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Photochemical C–F Activation Enables Defluorinative Alkylation of Trifluoroacetates and -Acetamides

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(47), P. 19648 - 19654

Published: Nov. 18, 2021

The installation of gem-difluoromethylene groups into organic structures remains a daunting synthetic challenge despite their attractive structural, physical, and biochemical properties. A very efficient retrosynthetic approach would be the functionalization single C–F bond from trifluoromethyl group. Recent advances in this line attack have enabled activation trifluoromethylarenes, but limit accessible motifs to only benzylic gem-difluorinated scaffolds. In contrast, trifluoroacetates enable use as bifunctional synthon. Herein, we report photochemically mediated method for defluorinative alkylation commodity feedstock: ethyl trifluoroacetate. novel mechanistic was identified using our previously developed diaryl ketone HAT catalyst hydroalkylation diverse suite alkenes. Furthermore, electrochemical studies revealed that more challenging radical precursors, namely trifluoroacetamides, could also functionalized via synergistic Lewis acid/photochemical activation. Finally, concise gem-difluoro analogs FDA-approved pharmaceutical compounds.

Language: Английский

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Photocatalytic hydrofluoroalkylation of alkenes with carboxylic acids

Nature Chemistry, Journal Year: 2023, Volume and Issue: 15(12), P. 1683 - 1692

Published: Nov. 13, 2023

Language: Английский

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Selective Defluoroallylation of Trifluoromethylarenes

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(36), P. 14120 - 14125

Published: Aug. 22, 2019

We report a fluoride-initiated coupling reaction between trifluoromethylarenes and allylsilanes to access allylated α,α-difluorobenzylic compounds. This method's utility is demonstrated through 30 mmol scale reaction, sequential allylation/derivatization protocol multiple examples of site-selective trifluoromethylarene allylation. Initial mechanistic studies suggest base-induced single electron transfer pathway responsible for the high efficiency selectivity this novel C–F substitution process.

Language: Английский

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Oxy-Difluoroalkylation of Allylamines with CO₂ via Visible-Light Photoredox Catalysis

Organic Letters, Journal Year: 2017, Volume and Issue: 20(1), P. 190 - 193

Published: Dec. 27, 2017

A selective oxy-difluoroalkylation of allylamines with carbon dioxide (CO2) via visible-light photoredox catalysis is reported. These multicomponent reactions are efficient and environmentally friendly to generate a series important 2-oxazolidinones functionalized difluoroalkyl groups. The good functional group tolerance, broad substrate scope, easy scalability, mild reaction conditions, facile functionalization products provide great potential for application in organic synthesis pharmaceutical chemistry.

Language: Английский

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Visible Light‐Induced Photocatalytic C−H Perfluoroalkylation of Quinoxalinones under Aerobic Oxidation Condition

Advanced Synthesis & Catalysis, Journal Year: 2019, Volume and Issue: 361(23), P. 5490 - 5498

Published: Sept. 16, 2019

Abstract An efficient approach using a photocatalytic strategy for C−H perfluoroalkylation of quinoxalinones under aerobic oxidation condition has been developed. Such transformation employs readily available sodium perfluoroalkanesulfinates as reagents and demonstrates good functional group compatibility, affording corresponding products in moderate to yields. Compared with previous procedures, this protocol uses oxygen oxidant, avoids the use external additive. A radical mechanism is involved reaction. magnified image

Language: Английский

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