Alkoxy Radicals See the Light: New Paradigms of Photochemical Synthesis

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 2429 - 2486

Published: Oct. 6, 2021

Alkoxy radicals are highly reactive species that have long been recognized as versatile intermediates in organic synthesis. However, their development has impeded due to a lack of convenient methods for generation. Thanks advances photoredox catalysis, enabling facile access alkoxy from bench-stable precursors and free alcohols under mild conditions, research interest this field renewed. This review comprehensively summarizes the recent progress radical-mediated transformations visible light irradiation. Elementary steps radical generation either or central reaction development; thus, each section is categorized discussed accordingly. Throughout review, we focused on different mechanisms well impact synthetic utilizations. Notably, catalytic abundant still early stage, providing intriguing opportunities exploit diverse paradigms.

Language: Английский

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Arylsulfonylacetamides as bifunctional reagents for alkene aminoarylation

Science, Journal Year: 2018, Volume and Issue: 361(6409), P. 1369 - 1373

Published: Sept. 28, 2018

Alkene aminoarylation with a single, bifunctional reagent is concise synthetic strategy. We report catalytic protocol for the addition of arylsulfonylacetamides across electron-rich alkenes complete anti-Markovnikov regioselectivity and excellent diastereoselectivity to provide 2,2-diarylethylamines. In this process, single-electron alkene oxidation enables carbon-nitrogen bond formation key benzylic radical poised Smiles-Truce 1,5-aryl shift. This reaction redox-neutral, exhibits broad functional group compatibility, occurs at room temperature loss sulfur dioxide. As process driven by visible light, uses readily available starting materials, demonstrates convergent synthesis, it well suited use in variety endeavors.

Language: Английский

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Strategies to Generate Nitrogen-centered Radicals That May Rely on Photoredox Catalysis: Development in Reaction Methodology and Applications in Organic Synthesis

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 2353 - 2428

Published: Oct. 8, 2021

For more than 70 years, nitrogen-centered radicals have been recognized as potent synthetic intermediates. This review is a survey designed for use by chemists engaged in target-oriented synthesis. summarizes the recent paradigm shift access to and application of N-centered enabled visible-light photocatalysis. broadens streamlines approaches many small molecules because photocatalysis conditions are mild. Explicit attention paid innovative advances N–X bonds radical precursors, where X = Cl, N, S, O, H. clarity, key mechanistic data noted, available. Synthetic applications limitations summarized illuminate tremendous utility photocatalytically generated radicals.

Language: Английский

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Nitrogen-Centered Radicals in Functionalization of sp² Systems: Generation, Reactivity, and Applications in Synthesis

Chemical Reviews, Journal Year: 2022, Volume and Issue: 122(9), P. 8181 - 8260

Published: March 14, 2022

The chemistry of nitrogen-centered radicals (NCRs) has plentiful applications in organic synthesis, and they continue to expand as our understanding these reactive species increases. utility intermediates is demonstrated the recent advances C–H amination (di)amination alkenes. Synthesis previously challenging structures can be achieved by efficient functionalization sp2 moieties without prefunctionalization, allowing for faster more streamlined synthesis. This Review addresses generation, reactivity, application NCRs, including, but not limited to, iminyl, aminyl, amidyl, aminium species. Contributions from early discovery up most examples have been highlighted, covering radical initiation, thermolysis, photolysis, and, recently, photoredox catalysis. Radical-mediated intermolecular (hetero)arenes occur with a variety complex amine precursors, generating aniline derivatives, an important class drug development. Functionalization olefins achievable high anti-Markovnikov regioselectivity allows access difunctionalized when intermediate carbon are trapped. Additionally, reactivity NCRs harnessed rapid construction N-heterocycles such pyrrolidines, phenanthridines, quinoxalines, quinazolinones.

Language: Английский

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Metal-Free C(sp²)–H/N–H Cross-Dehydrogenative Coupling of Quinoxalinones with Aliphatic Amines under Visible-Light Photoredox Catalysis

Organic Letters, Journal Year: 2018, Volume and Issue: 20(22), P. 7125 - 7130

Published: Oct. 29, 2018

A novel and efficient visible-light-induced C(sp2)–H/N–H cross-dehydrogenative coupling (CDC)-amination with both primary secondary aliphatic amines at room temperature in air is developed. This photocatalytic reaction allows the direct formation of 3-aminoquinoxalin-2(1H)-ones via CDC-amination absence any external oxidant added from outside. Preliminary mechanistic studies reveal that present proceeds through a radical process.

Language: Английский

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Photoredox Imino Functionalizations of Olefins

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 56(43), P. 13361 - 13365

Published: Aug. 31, 2017

Abstract Shown herein is that polyfunctionalized nitrogen heterocycles can be easily prepared by a visible‐light‐mediated radical cascade process. This divergent strategy features the oxidative generation of iminyl radicals and subsequent cyclization/radical trapping, which allows effective construction highly functionalized heterocycles. The reactions proceed efficiently at room temperature, utilize an organic photocatalyst, use simple readily available materials, generate, in single step, valuable building blocks would difficult to prepare other methods.

Language: Английский

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Practical and regioselective amination of arenes using alkyl amines

Nature Chemistry, Journal Year: 2019, Volume and Issue: 11(5), P. 426 - 433

Published: April 22, 2019

Language: Английский

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Light - driven deracemization enabled by excited - state electron transfer

Science, Journal Year: 2019, Volume and Issue: 366(6463), P. 364 - 369

Published: Oct. 17, 2019

Charging through the looking glass Asymmetric catalysis is a commonly applied technique to prepare just one of two mirror-image products in chemical reaction. But what if you already have compound want, stuck mixture left- and right-handed enantiomers? Shin et al. now show that light-induced electron transfer can trigger favorable succession proton hydrogen-atom steps, both which are susceptible biasing by catalysts, preferentially convert cyclic urea enantiomers into (see Perspective Wendlandt). Science , this issue p. 364 ; see also 304

Language: Английский

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Multicomponent synthesis of tertiary alkylamines by photocatalytic olefin-hydroaminoalkylation

Nature, Journal Year: 2018, Volume and Issue: 561(7724), P. 522 - 527

Published: Sept. 1, 2018

Language: Английский

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A Redox Strategy for Light-Driven, Out-of-Equilibrium Isomerizations and Application to Catalytic C–C Bond Cleavage Reactions

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(4), P. 1457 - 1462

Published: Jan. 10, 2019

We report a general protocol for the light-driven isomerization of cyclic aliphatic alcohols to linear carbonyl compounds. These reactions proceed via proton-coupled electron-transfer activation alcohol O–H bonds followed by subsequent C–C β-scission resulting alkoxy radical intermediates. In many cases, these redox-neutral isomerizations in opposition significant energetic gradient, yielding products that are less thermodynamically stable than starting materials. A mechanism is presented rationalize this out-of-equilibrium behavior may serve as model design other contrathermodynamic transformations driven excited-state redox events.

Language: Английский

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