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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Synthesis and site selective C–H functionalization of imidazo-[1,2-a]pyridines

Organic & Biomolecular Chemistry, Journal Year: 2023, Volume and Issue: 21(36), P. 7267 - 7289

Published: Jan. 1, 2023

Herein we disclose the synthesis and an overview of all functionalization reactions at each carbon atom, viz , C2, C3, C5, C6, C7 C8 imidazo[1,2- a ]pyridine.

Language: Английский

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TEMPO-Mediated Direct C(sp²)–H Alkoxylation/Aryloxylation of 1,4-Quinones

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

Published: Jan. 4, 2025

A convenient and efficient transition-metal-free method has been developed for the C(sp

Language: Английский

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Site-selective C5–H andN–H alkylation of unprotected 8-aminoquinolines

Chemical Communications, Journal Year: 2022, Volume and Issue: 58(31), P. 4893 - 4896

Published: Jan. 1, 2022

8-Aminoquinolines are the building blocks of many pharmaceutical compounds, which has motivated scientific community to develop new ways derivatize these compounds. In this work, we performed a site-selective C5-H and N-H alkylation 8-aminoquinolines using para-quinone methides under extremely mild conditions. was protecting group-free in metal-free alkylations were also carried out All corresponding products obtained high excellent yields.

Language: Английский

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HBF₄‐Catalyzed 3,6‐Bis‐diarylmethylation of Carbazoles withpara‐Quinone Methides

European Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 2022(46)

Published: Nov. 15, 2022

Abstract In this article, we demonstrate an atom economical, practical, mild and selective HBF 4 ‐catalyzed 1,6‐conjugate addition of carbazoles to para ‐Quinone Methides ( p ‐QMs) access 3,6‐bis‐diarylmethyl‐ mono‐diarylmethyl carbazoles. This metal additive free protocol provides convenient the substituted carbazole derivatives in moderate excellent yields with a good functional group tolerance. It was found that couple 3,6‐disubstituted showed interesting photophysical properties and, therefore, might potentially find some applications as host materials OLEDs.

Language: Английский

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Acid‐Catalyzed Regioselective Synthesis of α‐Diarylmethyl Substituted Phenols and para‐Quinone Methides in Water

Asian Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 11(8)

Published: July 2, 2022

Abstract A facile and efficient method for the synthesis of α ‐diarylmethyl substituted phenols from para ‐quinone methides ( p ‐QMs) with has been developed by using phosphoric acid as catalyst water green solvent under mild conditions. In addition, when TEMPO was added an additive reaction, diaryl‐substituted could be generated target product. The reactions show high functional group tolerance, good to excellent yields unique selectivity, a broad range motif containing phenol(s) quinones prepared through divergent methods. Furthermore, series control experiments were performed gain insights plausible mechanisms. These protocols have atomic economy, may significant implications construction C( sp 3 )−C( 2 ) bonds in organic synthesis.

Language: Английский

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Benzylic C H heteroarylation of 4-Methylphenols with 2H-Indazoles

Tetrahedron Letters, Journal Year: 2022, Volume and Issue: 105, P. 154053 - 154053

Published: Aug. 1, 2022

Language: Английский

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Five-membered ring systems: with more than one N atom

Progress in heterocyclic chemistry, Journal Year: 2023, Volume and Issue: unknown, P. 255 - 304

Published: Jan. 1, 2023

Language: Английский

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Magnesium-Mediated Umpolung Carboxylation of p-Quinone Methides with CO₂

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(20), P. 14640 - 14648

Published: Sept. 29, 2023

Magnesium-mediated reductive carboxylation of p-QMs with CO2 via an Umpolung strategy has been developed, which can be used for the preparation various aryl acetic acids. This protocol featured high atom economy, mild conditions, and operational simplicity. The creation this will unprecedentedly extend application to nucleophilic reagents.

Language: Английский

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