Photocatalytic Late-Stage C–H Functionalization

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(8), P. 4237 - 4352

Published: Jan. 24, 2023

The emergence of modern photocatalysis, characterized by mildness and selectivity, has significantly spurred innovative late-stage C–H functionalization approaches that make use low energy photons as a controllable source. Compared to traditional strategies, photocatalysis paves the way toward complementary and/or previously unattainable regio- chemoselectivities. Merging compelling benefits with workflow offers potentially unmatched arsenal tackle drug development campaigns beyond. This Review highlights photocatalytic strategies small-molecule drugs, agrochemicals, natural products, classified according targeted bond newly formed one. Emphasis is devoted identifying, describing, comparing main mechanistic scenarios. draws critical comparison between established ionic chemistry photocatalyzed radical-based manifolds. aims establish current state-of-the-art illustrate key unsolved challenges be addressed in future. authors aim introduce general readership functionalization, specialist practitioners evaluation methodologies, potential for improvement, future uncharted directions.

Language: Английский

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Sustainable Thioetherification via Electron Donor–Acceptor Photoactivation Using Thianthrenium Salts

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(22)

Published: March 16, 2022

Abstract The synthesis of sulfides has been widely studied because this functional subunit is prevalent in biomolecules and pharmaceuticals, as well being a useful synthetic platform for further elaboration. Thus, various methods to build C−S bonds have developed, but typically they require the use precious metals or harsh conditions. Electron donor–acceptor (EDA) complex photoactivation strategies emerged versatile sustainable ways achieve bond formation, avoiding challenges associated with previous methods. This work describes an open‐to‐air, photoinduced, site‐selective C−H thioetherification from readily available reagents via EDA formation that tolerates wide range different groups. Moreover, C(sp 2 )−halogen remain intact using protocol, allowing late‐stage installation sulfide motif bioactive scaffolds, while yet modification through more traditional C−X cleavage protocols. Additionally, mechanistic investigations support envisioned scenario.

Language: Английский

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A general electron donor–acceptor complex for photoactivation of arenes via thianthrenation

Chemical Science, Journal Year: 2022, Volume and Issue: 13(19), P. 5659 - 5666

Published: Jan. 1, 2022

General photoactivation of EDA complexes between arylsulfonium salts and 1,4-diazabicyclo[2.2.2]octane was discovered. This practical mode enables the generation aryl radicals for C–H functionalization arenes.

Language: Английский

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Sulfonium Salts as Acceptors in Electron Donor‐Acceptor Complexes

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(29)

Published: March 24, 2023

Abstract The photoactivation of electron donor‐acceptor complexes has emerged as a sustainable, selective and versatile strategy for the generation radical species. Electron (EDA) complexation, however, imposes electronic constraints on donor acceptor components this can limit range radicals that be generated using approach. New EDA complexation strategies exploiting sulfonium salts allow to from native functionality. For example, aryl salts, formed by activation arenes, serve in due their electron‐deficient nature. This “sulfonium tag” approach relaxes parent substrate dramatically expands complexation. In review, these new applications will introduced areas chemical space rendered accessible through innovation highlighted.

Language: Английский

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Photoinduced Copper-Catalyzed Late-Stage Azidoarylation of Alkenes via Arylthianthrenium Salts

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(25), P. 13542 - 13548

Published: June 12, 2023

The arylethylamine pharmacophore is conserved across a range of biologically active natural products and pharmaceuticals, particularly in molecules that act on the central nervous system. Herein, we present photoinduced copper-catalyzed azidoarylation alkenes at late stage with arylthianthrenium salts, allowing access to highly functionalized acyclic (hetero)arylethylamine scaffolds are otherwise difficult access. A mechanistic study consistent rac-BINAP-CuI-azide (2) as photoactive catalytic species. We show utility new method by expedient synthesis racemic melphalan four steps through C-H functionalization.

Language: Английский

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Organic Synthesis Using Nitroxides

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(16), P. 10302 - 10380

Published: Aug. 14, 2023

Nitroxides, also known as nitroxyl radicals, are long-lived or stable radicals with the general structure R1R2N–O•. The spin distribution over nitroxide N and O atoms contributes to thermodynamic stability of these radicals. presence bulky N-substituents R1 R2 prevents radical dimerization, ensuring their kinetic stability. Despite reactivity toward various transient C some nitroxides can be easily stored under air at room temperature. Furthermore, oxidized oxoammonium salts (R1R2N═O+) reduced anions (R1R2N–O–), enabling them act valuable oxidants reductants depending on oxidation state. Therefore, they exhibit interesting across all three states. Due fascinating properties, find extensive applications in diverse fields such biochemistry, medicinal chemistry, materials science, organic synthesis. This review focuses versatile For use other important fields, we will refer several articles. introductory part provides a brief overview history chemistry. Subsequently, key methods for preparing discussed, followed by an examination structural diversity physical properties. main portion this is dedicated reactions, wherein parent corresponding serve active species. It demonstrated that functional groups (such alcohols, amines, enolates, alkanes among others) efficiently oxidized. These oxidations carried out using catalysts combination stoichiometric terminal oxidants. By reducing anions, become effective reagents intriguing Nitroxides possess ability selectively react making useful terminating cascade reactions forming alkoxyamines. Depending structure, alkoxyamines weak C–O bonds, allowing thermal generation through reversible bond cleavage. Such thermally generated participate transformations, discussed end review. application strategy natural product synthesis presented.

Language: Английский

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Cu-Mediated Thianthrenation and Phenoxathiination of Arylborons

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(18), P. 10431 - 10440

Published: April 26, 2023

Great success in synthetic chemistry is motivated by the development of novel and reactive linchpins for carbon-carbon carbon-heteroatom bond formation reactions, which has dramatically altered chemists' approach to building molecules. Herein, we report ready synthesis aryl sulfonium salts, a versatile electrophilic linchpin, via Cu-mediated thianthrenation phenoxathiination commercially available arylborons with thianthrene phenoxathiine, providing series salts high efficiency. More importantly, leveraging sequential Ir-catalyzed C-H borylation arylborons, formal arenes also achieved. The undirected normally occurred at less steric hindrance position, thus complementary method comparison thianthrenation. This process capable late-stage functionalization pharmaceuticals, might find wide applications both industry academic sectors.

Language: Английский

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Insights into Single-Electron-Transfer Processes in Frustrated Lewis Pair Chemistry and Related Donor–Acceptor Systems in Main Group Chemistry

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(15), P. 9653 - 9675

Published: July 11, 2023

The activation and utilization of substrates mediated by Frustrated Lewis Pairs (FLPs) was initially believed to occur solely via a two-electron, cooperative mechanism. More recently, the occurrence single-electron transfer (SET) from base acid observed, indicating that mechanisms proceed one-electron-transfer processes are also feasible. As such, SET in FLP systems leads formation radical ion pairs, which have recently been more frequently observed. In this review, we aim discuss seminal findings regarding established insights into chemistry as well highlight examples process. addition, applications reported main group radicals will be reviewed discussed context understanding systems.

Language: Английский

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A General Platform for Visible Light Sulfonylation Reactions Enabled by Catalytic Triarylamine EDA Complexes

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(4), P. 2583 - 2592

Published: Jan. 17, 2024

Catalytic electron donor–acceptor (EDA) complexes have recently emerged as a powerful and sustainable alternative to iridium- ruthenium-based photoredox synthetic methods. Yet, these remain underexplored reliant on the use of meticulously designed acceptors that require previous installation. Herein, we report novel EDA complex employing tris(4-methoxyphenyl) amine catalytic donor for sulfonylation alkenes using inexpensive readily available sulfonyl chlorides. Applying this operationally simple, visible-light-mediated general platform, both redox-neutral net-reductive functionalization more than 60 substrates, encompassing vinylic or allylic sulfonylation, hydrosulfonylation, sulfamoylation activated unactivated alkynes.

Language: Английский

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Aryl sulfonium salt electron donor-acceptor complexes for halogen atom transfer: Isocyanides as tunable coupling partners

Chem, Journal Year: 2024, Volume and Issue: 10(4), P. 1240 - 1251

Published: Feb. 13, 2024

The photoactivation of sulfonium salt EDA (electron donor-acceptor) complexes provides a mild platform for aryl-radical-mediated halogen atom transfer activation wide range functionalized alkyl iodides, including tertiary iodides. Using an aryl with carbonate as inexpensive donor complex formation, the general reaction has been applied in divergent, metal-free photochemical approach to nitriles and amides. This divergency was made possible by tuning isocyanide radical traps. For example, identification readily accessible, bench-stable, crystalline amide containing grants access nitrile products complete selectivity.

Language: Английский

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