Metallaphotoredox: The Merger of Photoredox and Transition Metal Catalysis

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 1485 - 1542

Published: Nov. 18, 2021

The merger of photoredox catalysis with transition metal catalysis, termed metallaphotoredox has become a mainstay in synthetic methodology over the past decade. Metallaphotoredox combined unparalleled capacity for bond formation broad utility photoinduced electron- and energy-transfer processes. Photocatalytic substrate activation allowed engagement simple starting materials metal-mediated bond-forming Moreover, electron or energy transfer directly key organometallic intermediates provided novel modes entirely complementary to traditional catalytic platforms. This Review details contextualizes advancements molecule construction brought forth by metallaphotocatalysis.

Language: Английский

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Selective functionalization of methane, ethane, and higher alkanes by cerium photocatalysis

Science, Journal Year: 2018, Volume and Issue: 361(6403), P. 668 - 672

Published: July 26, 2018

With the recent soaring production of natural gas, use methane and other light hydrocarbon feedstocks as starting materials in synthetic transformations is becoming increasingly economically attractive, although it remains chemically challenging. We report development photocatalytic C-H amination, alkylation, arylation methane, ethane, higher alkanes under visible irradiation at ambient temperature. High catalytic efficiency (turnover numbers up to 2900 for 9700 ethane) selectivity were achieved using abundant, inexpensive cerium salts photocatalysts. Ligand-to-metal charge transfer excitation generated alkoxy radicals from simple alcohols that turn acted hydrogen atom catalysts. The mixed-phase gas/liquid reaction was adapted continuous flow, enabling efficient gaseous scalable transformations.

Language: Английский

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Complementary Strategies for Directed C(sp³)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 57(1), P. 62 - 101

Published: Dec. 5, 2017

Abstract The functionalization of C(sp 3 )−H bonds streamlines chemical synthesis by allowing the use simple molecules and providing novel synthetic disconnections. Intensive recent efforts in development new reactions based on C−H have led to its wider adoption across a range research areas. This Review discusses strengths weaknesses three main approaches: transition‐metal‐catalyzed activation, 1, n ‐hydrogen atom transfer, carbene/nitrene for directed unactivated bonds. For each strategy, scope, reactivity different bonds, position reacting relative directing group, stereochemical outcomes are illustrated with examples literature. aim this is provide guidance inspire future area.

Language: Английский

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Photoredox-Mediated Routes to Radicals: The Value of Catalytic Radical Generation in Synthetic Methods Development

ACS Catalysis, Journal Year: 2017, Volume and Issue: 7(4), P. 2563 - 2575

Published: March 14, 2017

Photoredox catalysis has experienced a revitalized interest from the synthesis community during past decade. For example, photoredox/Ni dual protocols have been developed to overcome several inherent limitations of palladium-catalyzed cross-couplings by invoking single-electron transmetalation pathway. This Perspective highlights advances made our laboratory since inception cross-coupling benzyltrifluoroborates with aryl bromides. In addition broadening scope trifluoroborate coupling partners, research using readily oxidized hypervalent silicates as radical precursors that demonstrate functional group compatibility is highlighted. The pursuit electrophilic partners beyond (hetero)aryl bromides also led incorporation new classes C(sp2)-hybridized substrates into light-mediated cross-coupling. Advances expand toolbox utilizing feedstock chemicals (e.g., aldehydes) access radicals were previously inaccessible trifluoroborates and are emphasized. Additionally, organic photocatalysts investigated replacements for their expensive iridium- ruthenium-based counterparts. Lastly, net C–H functionalization partner in an effort improve atom economy presented. An underlying theme all these studies value generating catalytic manner, rather than stoichiometrically.

Language: Английский

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Remote carboxylation of halogenated aliphatic hydrocarbons with carbon dioxide

Nature, Journal Year: 2017, Volume and Issue: 545(7652), P. 84 - 88

Published: May 1, 2017

Language: Английский

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Remote C–H Functionalization via Selective Hydrogen Atom Transfer

Synthesis, Journal Year: 2018, Volume and Issue: 50(08), P. 1569 - 1586

Published: Feb. 12, 2018

The selective functionalization of remote C–H bonds via intramolecular hydrogen atom transfer (HAT) is transformative for organic synthesis. This radical-mediated strategy provides access to novel reactivity that complementary closed-shell pathways. As modern methods mild generation radicals are continually developed, inherent selectivity paradigms HAT mechanisms offer unparalleled opportunities developing new strategies functionalization. review outlines the history, recent advances, and mechanistic underpinnings as a guide addressing ongoing challenges in this arena. 1 Introduction 2 Nitrogen-Centered Radicals 2.1 sp3 N-Radical Initiation 2.2 sp2 3 Oxygen-Centered 3.1 Carbonyl Diradical 3.2 Alkoxy Radical 3.3 Non-alkoxy 4 Carbon-Centered 4.1 C-Radical 4.2 5 Conclusion

Language: Английский

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Site-Selective C–H Functionalization by Decatungstate Anion Photocatalysis: Synergistic Control by Polar and Steric Effects Expands the Reaction Scope

ACS Catalysis, Journal Year: 2017, Volume and Issue: 8(1), P. 701 - 713

Published: Dec. 5, 2017

The synergistic control of the SH2 transition states hydrogen abstraction by polar and steric effects provides a promising strategy in achieving site-selective C(sp3)–H functionalization under decatungstate anion photocatalysis. By using this photocatalytic approach, C–H bonds alkanes, alcohols, ethers, ketones, amides, esters, nitriles, pyridylalkanes were functionalized site-selectively. In remarkable case 2,4-disubstituted cyclohexanone bearing five methyl, methylene, three methine bonds, one bond isoamyl tether was selectively functionalized.

Language: Английский

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Toolbox for Distal C–H Bond Functionalizations in Organic Molecules

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(6), P. 5682 - 5841

Published: Oct. 18, 2021

Transition-metal-catalyzed C–H activation has developed a contemporary approach to the omnipresent area of retrosynthetic disconnection. Scientific researchers have been tempted take help this methodology plan their synthetic discourses. This paradigm shift helped in development industrial units as well, making synthesis natural products and pharmaceutical drugs step-economical. In vast zone bond activation, functionalization proximal bonds gained utmost popularity. Unlike bonds, distal is more strenuous requires distinctly specialized techniques. review, we compiled various methods adopted functionalize mechanistic insights within each these procedures, scope methodology. With give complete overview expeditious progress made field organic chemistry while also highlighting its pitfalls, thus leaving open for further modifications.

Language: Английский

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New Redox Strategies in Organic Synthesis by Means of Electrochemistry and Photochemistry

ACS Central Science, Journal Year: 2020, Volume and Issue: 6(8), P. 1317 - 1340

Published: July 16, 2020

As the breadth of radical chemistry grows, new means to promote and regulate single-electron redox activities play increasingly important roles in driving modern synthetic innovation. In this regard, photochemistry electrochemistry-both considered as niche fields for decades-have seen an explosive renewal interest recent years gradually have become a cornerstone organic chemistry. Outlook article, we examine current state-of-the-art areas electrochemistry photochemistry, well nascent area electrophotochemistry. These techniques employ external stimuli activate molecules imbue privileged control reaction progress selectivity that is challenging traditional chemical methods. Thus, they provide alternative entries known reactive intermediates enable distinct strategies were previously unimaginable. Of many hallmarks, electro- are often classified "green" technologies, promoting reactions under mild conditions without necessity potent wasteful oxidants reductants. This reviews most growth these with special emphasis on conceptual advances given rise enhanced accessibility tools trade.

Language: Английский

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Photochemical Generation of Nitrogen-Centered Amidyl, Hydrazonyl, and Imidyl Radicals: Methodology Developments and Catalytic Applications

ACS Catalysis, Journal Year: 2017, Volume and Issue: 7(8), P. 4999 - 5022

Published: June 19, 2017

During the past decade, visible light photocatalysis has become a powerful synthetic platform for promoting challenging bond constructions under mild reaction conditions. These photocatalytic systems rely on harnessing energy purposes through generation of reactive but controllable free radical species. Recent progress in area established it as an enabling catalytic strategy and selective nitrogen-centered radicals. The application activation amides, hydrazones, imides represents valuable approach facilitating formation Within span only couple years, significant been made expediting amidyl, hydrazonyl, imidyl radicals from variety precursors. This Perspective highlights recent advances light-mediated these A particular emphasis is placed unique ability accessing elusive manifolds construction diversely functionalized nitrogen-containing motifs nontraditional disconnections contemporary chemistry.

Language: Английский

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