The Persistent Radical Effect in Organic Synthesis

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 59(1), P. 74 - 108

Published: May 22, 2019

Abstract Radical–radical couplings are mostly nearly diffusion‐controlled processes. Therefore, the selective cross‐coupling of two different radicals is challenging and not a synthetically valuable transformation. However, if have lifetimes they generated at equal rates, will become dominant process. This high cross‐selectivity based on kinetic phenomenon called persistent radical effect (PRE). In this Review, an explanation PRE supported by simulations simple model systems provided. Radical stabilities discussed within context their lifetimes, various examples PRE‐mediated radical–radical in synthesis summarized. It shown that restricted to coupling with transient radical. If one partner longer‐lived than other radical, operates achieved. important point expands scope chemistry. The Review divided into parts, namely 1) or organic 2) “radical–metal crossover reactions”; here, metal‐centered species more generally transition‐metal complexes able react discussed—a field has flourished recently.

Language: Английский

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Photoredox-Catalyzed C–H Functionalization Reactions

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 1925 - 2016

Published: Sept. 29, 2021

The fields of C–H functionalization and photoredox catalysis have garnered enormous interest utility in the past several decades. Many different scientific disciplines relied on strategies including natural product synthesis, drug discovery, radiolabeling, bioconjugation, materials, fine chemical synthesis. In this Review, we highlight use reactions. We separate review into inorganic/organometallic catalysts organic-based catalytic systems. Further subdivision by reaction class─either sp2 or sp3 functionalization─lends perspective tactical for these methods synthetic applications.

Language: Английский

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Recent advances in photoredox and nickel dual-catalyzed cascade reactions: pushing the boundaries of complexity

Chemical Science, Journal Year: 2020, Volume and Issue: 11(16), P. 4051 - 4064

Published: Jan. 1, 2020

Cascade reactions that produce multiple chemical bonds in one synthetic operation are important the efficient construction of complex molecules.

Language: Английский

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Metal-Catalyzed Intermolecular Hydrofunctionalization of Allenes: Easy Access to Allylic Structures via the Selective Formation of C–N, C–C, and C–O Bonds

Chemical Reviews, Journal Year: 2020, Volume and Issue: 120(24), P. 13545 - 13598

Published: Dec. 10, 2020

Following a strong regain of interest over the past 20 years in chemistry allenes, this "forgotten" family unsaturated molecules is undergoing renaissance. In context, metal-catalyzed hydrofunctionalization allenes nowadays one most studied transformations. The latter great because it opens way to produce selectively functionalized allylic structures. These motifs are important synthesis, particularly for formation asymmetric centers. Hydrofunctionalization also totally atom economical strategy, avoiding generation any waste, Compared main pathway obtain (aka Tsuji-Trost substitution), does not require prefunctionalization starting material with leaving group. This review presents state art exploration all existing transition methods allowing selective intermolecular N–H, C–H, and O–H nucleophiles or electrophiles.

Language: Английский

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Transition metal-catalysed allylic functionalization reactions involving radicals

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 49(17), P. 6186 - 6197

Published: Jan. 1, 2020

In this tutorial review, different types of transition metal-catalysed allylic functionalization reactions involving radicals are highlighted.

Language: Английский

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Switchable Divergent Synthesis Using Photocatalysis

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(3), P. 1857 - 1878

Published: Jan. 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.

Language: Английский

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Transition-metal-catalyzed C–H allylation reactions

Chem, Journal Year: 2020, Volume and Issue: 7(3), P. 555 - 605

Published: Nov. 13, 2020

Language: Английский

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Der “Persistent Radical Effect” in der organischen Chemie

Angewandte Chemie, Journal Year: 2019, Volume and Issue: 132(1), P. 74 - 110

Published: May 22, 2019

Abstract Radikal‐Radikal‐Kupplungen sind nahezu diffusionskontrollierte Prozesse. Daher selektive Kreuzkupplungen zweier unterschiedlicher Radikale schwierig zu realisieren und stellen somit synthetisch nicht wertvolle Prozesse dar. Wenn die beiden allerdings eine unterschiedliche Lebensdauer aufweisen in gleichen Raten gebildet werden, wird Kreuzkupplung zum dominierenden Prozess. Die hohe Kreuzselektivität basiert auf einem kinetischen Phänomen, dem “Persistent Radical Effect” (PRE). In diesem Aufsatz von Simulationen einfacher Modellsysteme gestützte Erklärung des PRE geliefert. Weiter werden Stabilität Radikalen Bezug ihre verschiedene Beispiele für PRE‐vermittelte der Synthese diskutiert. Es gezeigt, dass Kupplungen persistenter mit transienten beschränkt ist. Der einhergehender hoher greift bereits, wenn ein Kupplungspartner langlebiger als das andere transiente Radikal Diese Tatsache erweitert signifikant Anwendungsgebiet PRE‐vermittelter Radikalchemie. Dieser ist zwei Teile aufgeteilt: 1) Kupplung oder organischer 2) Radikal‐Metall‐Kreuzungsreaktionen; hierbei Metall‐zentrierte Radikalspezies allgemeiner langlebige Übergangsmetallkomplexe, welche reagieren, diskutiert – Gebiet, jüngst stark expandiert

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Orthogonal Regulation of Nucleophilic and Electrophilic Sites in Pd‐Catalyzed Regiodivergent Couplings between Indazoles and Isoprene

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(15), P. 8321 - 8328

Published: Jan. 19, 2021

Abstract Depending on the reactant property and reaction mechanism, one major regioisomer can be favored in a that involves multiple active sites. Herein, an orthogonal regulation of nucleophilic electrophilic sites regiodivergent hydroamination isoprene with indazoles is demonstrated. Under Pd‐hydride catalysis, 1,2‐ or 4,3‐insertion pathway respect to could controlled by choice ligands. In terms indazoles, occurs at either N 1 ‐ 2 ‐position governed acid co‐catalysts. Preliminary experimental studies have been performed rationalize mechanism regioselectivity. This study not only contributes practical tool for selective functionalization isoprene, but also provides guide manipulate regioselectivity ‐functionalization indazoles.

Language: Английский

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Hydroaminoalkylation for the Catalytic Addition of Amines to Alkenes or Alkynes: Diverse Mechanisms Enable Diverse Substrate Scope

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(26), P. 11459 - 11481

Published: June 22, 2022

Hydroaminoalkylation is a powerful, atom-economic catalytic reaction for the of amines with alkenes and alkynes. This C–H functionalization allows alkylation using simple or alkynes as alkylating agents. transformation has significant potential transformative approaches in pharmaceutical, agrochemical, fine chemical industries preparation selectively substituted N-heterocycles shows promise materials science synthesis functional responsive aminated materials. Different early transition-metal, late photoredox catalysts mediate hydroaminoalkylation by distinct mechanistic pathways. These insights have resulted development new conditions to realize broad range substrates: activated unactivated, terminal internal, C–C double triple bonds aryl alkyl primary, secondary, tertiary amines, including N-heterocyclic amines. By deploying select specific substrate combinations, control over regioselectivity, diastereoselectivity, enantioselectivity been realized. Key barriers widespread adoption this include air moisture sensitivity transition-metal well heavy dependence on amine protecting directing groups photocatalytic routes. Advances improved catalyst robustness, scope, regio-/stereoselective reactions early- catalysts, catalysis, are highlighted, opportunities further included. perspective that be disruptive strategy from alkenes.

Language: Английский

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