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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Tunable Key [3 + 2] and [2 + 1] Cycloaddition of Enaminones and α-Diazo Compounds for the Synthesis of Isomeric Isoxazoles: Metal-Controlled Selectivity

Organic Letters, Journal Year: 2023, Volume and Issue: 25(12), P. 2139 - 2144

Published: March 22, 2023

The three-component reactions of enaminones, α-diazo esters/ketones, and t-butyl nitrite (TBN) for the switchable synthesis isomeric isoxazoles have been realized. catalysis with Cu(II) salt provides 3,4-disubsituted via [3 + 2] cycloaddition. On other hand, Ag(I) identical substrates leads to reversed C3 C4 substitution based on a key [2 1]

Language: Английский

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Recent advances in transition metal-catalyzed transformations in N,N-disubstituted enaminones

Tetrahedron Letters, Journal Year: 2023, Volume and Issue: 130, P. 154766 - 154766

Published: Sept. 26, 2023

Language: Английский

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Recent Advances in Electrochemical Cascade Cyclization Reactions

Synthesis, Journal Year: 2023, Volume and Issue: 55(18), P. 2911 - 2925

Published: Feb. 20, 2023

Abstract This review highlights recent progress in electrochemical cascade cyclization reactions for the synthesis of carbon rings and heterocycles, such as pyridines, quinolines, phenanthridines, cinnolines, 1,4-dihydroquinolines, oxindoles, imidazo[1,5-α]pyridines, imidazoles, etc. The works included herein are introduced two major sections heterocycle construction carbocycle reactions, covering reported from 2012 to 2022. 1 Introduction 2 Electrochemical Cascade Cyclization Synthesis Heterocycles 2.1 Pyridines, Quinolines, Phenanthridines, Cinnolines 2.2 1,4-Dihydroquinolines, Hexacyclic Sulfonamides, Thiazines 2.3 Hydroisoquinolinones Hydroquinolinones 2.4 Quinazolin-4(3H)-ones 2.5 4H-3,1-Benzoxazines 2.6 Oxindoles 2.7 Indolines Indoles 2.8 Imidazo[1,5-α]pyridines Imidazoles 2.9 Imidazolones, Imidazolidinones, Oxazolones, Oxazolidinones 2.10 Benzoxazoles, Oxazolines, Isoxazolines 2.11 Furans Dihydrofurans 2.12 Indolizines, Pyrazoles, Triazolium Inner Salts 2.13 Sulfonated Benzothiophenes, Thiazoles, Dihydrothiazoles, 1,3,4-Thiadiazoles 2.14 Lactones 3 Construction Carbocycles 3.1 Carbon Polycycles Spiroindenes 3.2 Difluoroacyl (Hetero)arenes Indenones 4 Conclusion

Language: Английский

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Three-Component Fusion to Pyrazolo[5,1-a]isoquinolines via Rh-Catalyzed Multiple Order Transformation of Enaminones

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(7), P. 4833 - 4838

Published: March 22, 2023

A facile and practical method for the synthesis of fused tricyclic pyrazolo[5,1-a]isoquinolines has been realized via reactions enaminones, hydrazine hydrochloride, internal alkynes. By means Rh catalysis, extraordinary high-order bond functionalization, including transformation aryl C–H, ketone C═O, alkenyl C–N bonds in marks major feature cascade reactions. The results disclose individual advantage enaminones design novel efficient synthetic methods.

Language: Английский

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Copper‐Catalyzed Oxidative [1+2+1+2] Cascade Cyclization of N,N‐Dimethyl Enaminones with Benzylamines: A Facile Access to Functionalized 1,4‐Dihydropyridines

Chemistry - A European Journal, Journal Year: 2023, Volume and Issue: 29(28)

Published: Feb. 24, 2023

Using benzylamines as the C4 source of 1,4-dihydropyridines (1,4-DHPs), a Cu-catalyzed oxidative [1+2+1+2] cascade cyclization for synthesis 1,4-DHPs was firstly developed. A broad range easily available N,N-dimethyl enaminones and are employed smoothly to provide diverse with high efficiency. This method is performed by one-pot C(sp3 )-H bond functionalization/C(sp3 )-N cleavage/cyclization strategy form simultaneously two )-C(sp2 ) bonds, C(sp2 1,4-DHP ring.

Language: Английский

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Photocatalytic Annulation of Enaminones with Thioureas for the Synthesis of 2-Aminothiazoles via Tandem C–S and C–N Bond Formation

Synthesis, Journal Year: 2024, Volume and Issue: 56(16), P. 2565 - 2571

Published: April 26, 2024

Abstract Visible-light photocatalytic reactions between enaminones and thioureas leading to thiazole products have been achieved. The annulation process consists of tandem C–S C–N bond formation by running under air atmosphere at ambient temperature. Broad substrate tolerance the sustainable protocol has verified practical synthesis divergent thiazoles with both monocyclic fused cyclic structures.

Language: Английский

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Facile synthesis of α-sulfonyl ketoximes from alkenes using sodium sulfinate and NaNO₂ in water

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(18), P. 5054 - 5060

Published: Jan. 1, 2024

We have developed a new synthesis method for α-sulfonyl ketoximes from pyridine alkenes, sodium sulfinate, and NaNO 2 in water. This three-component approach allows the one-step formation of C–N C–S bonds under mild conditions.

Language: Английский

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Catalyst-free reactions of anilines with β-chloroenones: synthesis of α-chloroenaminones and 1,4-benzodiazepines

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: 22(45), P. 8857 - 8868

Published: Jan. 1, 2024

The Michael addition of anilines to β-chloroenones gives enaminones by the elimination hydrochloric acid (HCl). These are transformed into α-chloroenaminones

Language: Английский

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Iridium-catalyzed reduction of o-hydroxyl phenyl enaminones for the synthesis propiophenones and their application in 3-methyl chromone synthesis

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 1, 2024

A method of reducing

Language: Английский

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