N-Protonated Acridinium Catalyst Enables Anti-Markovnikov Hydration of Unconjugated Tri- and Disubstituted Olefins

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: 147(6), P. 4736 - 4742

Published: Jan. 31, 2025

The preparation of alcohols with anti-Markovnikov selectivity directly from olefins and water is a sought-after reaction due to its atom-economy potential cost-effectiveness. Herein, we present the first general method for direct, catalytic hydration unconjugated tri- disubstituted olefins. key advancement made possible by an oxidative (E*red = 2.15 V) N-H acridinium catalyst, which allowed functionalization alkenes that were previously unreactive in such transformations their high oxidation potential. developed protocol not limited but also enables other hydrofunctionalizations, as hydroetherifications, following same mechanistic pathway.

Language: Английский

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Photocatalytic Decarboxylative Alkylation of Cyclic Imine–BF₃ Complexes: A Modular Route to Functionalized Azacycles

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 12, 2024

Alkyl radicals generated via an acridine photocatalyzed decarboxylation reaction of feedstock carboxylic acids engage with a range cyclic imine-BF

Language: Английский

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Electro-oxidative Deoxyfluorination of Arenes with NEt₃·3HF

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 27, 2025

This report describes the design, development, and optimization of an electrochemical deoxyfluorination arenes using a tetrafluoropyridine-derived leaving group. NEt3·3HF serves as fluoride source, reactions are conducted either constant potential or current electrolysis in undivided cell. Mechanistic studies support net oxidative pathway, which initial single-electron oxidation generates radical cation intermediate that is trapped by fluoride. The resulting undergoes second reaction, followed loss group to yield fluoroarene product.

Language: Английский

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Arene and Heteroarene Functionalization Enabled by Organic Photoredox Catalysis

Accounts of Chemical Research, Journal Year: 2025, Volume and Issue: unknown

Published: March 12, 2025

ConspectusAromatic functionalization reactions are some of the most fundamental transformations in organic chemistry and have been a mainstay chemical synthesis for over century. Reactions such as electrophilic nucleophilic aromatic substitution (EAS SNAr, respectively) represent two reaction classes arene elaboration still today typify utilized methods functionalization. Despite reliable reactivity accessed by these venerable transformations, space that can be EAS SNAr is inherently limited due to electronic requirements substrate. In case EAS, highly active electrophiles paired with electron-neutral electron-rich (hetero)arenes. For electron-deficient (hetero)arenes possess appropriate nucleofuges (halides, -NO2, etc.) required reactivity. The inherent limitations on (hetero)arene presented an opportunity develop alternative access increased expand arsenal available synthetic chemists.For past decade, our research has concentrated developing novel functionalization, particular focus arenes applying late-stage Specifically, undergo single electron oxidation photoredox catalyst under irradiation, forming cation radicals. These radicals act key intermediates various transformations. While typically unreactive toward nucleophiles, reactive capable engaging common nucleophiles.This Account details dichotomy via radicals: C-H nucleophiles aerobic conditions or radical accelerated (CRA-SNAr) anaerobic settings. Based experimental computational studies, we propose reversible addition occur at ipso-, para-, ortho-positions relative electron-releasing group. Under conditions, formed para- ortho-addition additional irreversible step, resulting major outcome. Conversely, absence external oxidant, not observed, ipso-addition predominates, releasing alcohol HF nucleofuge, leading products. Building success also explored their applications positron emission tomography (PET) radiotracer development. Both 18F- 11CN- applied radiofluorination radiocyanation arenes, respectively. Applications radiotracers synthesized demonstrated preclinical clinical models.

Language: Английский

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Photocatalytic C−H Functionalization Utilizing Acridine−Lewis Acid Complexes and Pyridine N-oxide Based HAT Catalysts

Tetrahedron, Journal Year: 2025, Volume and Issue: unknown, P. 134683 - 134683

Published: April 1, 2025

Language: Английский

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Beyond the Zincke reaction: Modern advancements in the synthesis and applications of N-aryl pyridinium salts

Tetrahedron, Journal Year: 2024, Volume and Issue: 162, P. 134119 - 134119

Published: June 20, 2024

Language: Английский

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Acridine/Lewis Acid Complexes as Powerful Photocatalysts: A Combined Experimental and Mechanistic Study

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(19), P. 14574 - 14585

Published: Sept. 16, 2024

A class of in-situ generated Lewis acid (LA) activated acridine complexes is reported, which act as potent photochemical catalysts for the oxidation a variety protected secondary amines. Acridine/LA exhibit tunable excited state reduction potentials ranging from +2.07 to 2.38 V vs. SCE. The ytterbium triflate complex 3,6-di-t-butyl-9-mesitylacridine catalyzes Giese-type reaction Boc-protected amines with challenging conjugate acceptors such acrylates, that are inaccessible analogous acridinium (t-Bu-Mes-Acr⊕) catalyzed reaction. mechanism this was investigated using suite physical organic probes including intramolecular 13C kinetic isotope effects (KIEs), variable time normalization analysis (VTNA) kinetics, determination redox potentials, and computational studies. In by t-Bu-Mes-Acr⊕, mechanistic studies consistent single-electron transfer (SET) ground-state reduced t-Bu-Mes-Acr• α-keto radical intermediate first irreversible step in catalytic cycle. Intriguingly, we find acridine/LA better ground reductants (-0.72 -0.74 vs SCE) relative (-0.59 predict increased substrate reactivity stems lower energy barrier key SET event.

Language: Английский

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Direct construction of imidazoles via oxidative C(sp3)–H amination and annulation of aryethylamines by a Single-Atom cobalt catalyst

Journal of Catalysis, Journal Year: 2024, Volume and Issue: 439, P. 115774 - 115774

Published: Sept. 26, 2024

Language: Английский

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Modular Assembly of Acridines by Integrating Photo‐Excitation of o‐Alkyl Nitroarenes with Copper‐Promoted Cascade Annulation

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: unknown

Published: July 23, 2024

Abstract Acridine frameworks stand as pivotal architectural elements in pharmaceuticals and photocatalytic applications, owing to their chemical adaptability, biological activity, unique excited‐state dynamics. Conventional synthetic routes often entail specialized starting materials, anaerobic or moisture‐free conditions, elaborate multi‐stage manipulations for incorporating diverse functionalities. Herein, we present a convergent approach integrating photo‐excitation of readily available ortho ‐alkyl nitroarenes with copper‐promoted cascade annulation. This innovative system enables an aerobic, one‐pot reaction o‐ alkyl arylboronic acids, thereby streamlining the modular construction wide array acridine derivatives various functional groups. encompasses symmetrical, unsymmetrical polysubstituted varieties, some which are otherwise exceptionally difficult synthesize. Furthermore, it significantly improves production structurally varied acridinium salts, featuring enhanced photophysical properties, high excited state potentials ( E * red =2.08–3.15 V), exhibiting superior performance intricate photoredox transformations.

Language: Английский

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Modular Assembly of Acridines by Integrating Photo‐Excitation of o‐Alkyl Nitroarenes with Copper‐Promoted Cascade Annulation

Angewandte Chemie, Journal Year: 2024, Volume and Issue: 136(42)

Published: July 23, 2024

Abstract Acridine frameworks stand as pivotal architectural elements in pharmaceuticals and photocatalytic applications, owing to their chemical adaptability, biological activity, unique excited‐state dynamics. Conventional synthetic routes often entail specialized starting materials, anaerobic or moisture‐free conditions, elaborate multi‐stage manipulations for incorporating diverse functionalities. Herein, we present a convergent approach integrating photo‐excitation of readily available ortho ‐alkyl nitroarenes with copper‐promoted cascade annulation. This innovative system enables an aerobic, one‐pot reaction o‐ alkyl arylboronic acids, thereby streamlining the modular construction wide array acridine derivatives various functional groups. encompasses symmetrical, unsymmetrical polysubstituted varieties, some which are otherwise exceptionally difficult synthesize. Furthermore, it significantly improves production structurally varied acridinium salts, featuring enhanced photophysical properties, high excited state potentials ( E * red =2.08–3.15 V), exhibiting superior performance intricate photoredox transformations.

Language: Английский

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