A Diastereoselective Catalytic Approach to Pentasubstituted Pyrrolidines by Tandem Anionic‐Radical Cross‐Over Reactions

Jahn, Ullrich; Hidasová, Denisa; Cı́sařová, Ivana; Pohl, Radek

doi:10.1002/adsc.202101172

Cited by 3 publications

(2 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In these cascades, enolates 236 are generated elegantly through Michael addition of lithium amides 234 to α,β-unsaturated esters 235 . This sequence was further explored, and tri-, tetra-, as well as pentasubstituted pyrrolidines could be accessed. Instead of Li amides, ester enolates were also implemented as nucleophiles in the initial Michael addition, and after oxidative radical cyclization, cyclopentanes , were obtained.…”

Section: Nitroxides In Free-radical Chemistrymentioning

confidence: 99%

Organic Synthesis Using Nitroxides

Leifert

Studer

2023

Chem. Rev.

View full text Add to dashboard Cite

Nitroxides, also known as nitroxyl radicals, are long-lived or stable radicals with the general structure R 1 R 2 N−O • . The spin distribution over the nitroxide N and O atoms contributes to the thermodynamic stability of these radicals. The presence of bulky N-substituents R 1 and R 2 prevents nitroxide radical dimerization, ensuring their kinetic stability. Despite their reactivity toward various transient C radicals, some nitroxides can be easily stored under air at room temperature. Furthermore, nitroxides can be oxidized to oxoammonium salts (R 1 R 2 N�O + ) or reduced to anions (R 1 R 2 N−O − ), enabling them to act as valuable oxidants or reductants depending on their oxidation state. Therefore, they exhibit interesting reactivity across all three oxidation states. Due to these fascinating properties, nitroxides find extensive applications in diverse fields such as biochemistry, medicinal chemistry, materials science, and organic synthesis. This review focuses on the versatile applications of nitroxides in organic synthesis. For their use in other important fields, we will refer to several review articles. The introductory part provides a brief overview of the history of nitroxide chemistry. Subsequently, the key methods for preparing nitroxides are discussed, followed by an examination of their structural diversity and physical properties. The main portion of this review is dedicated to oxidation reactions, wherein parent nitroxides or their corresponding oxoammonium salts serve as active species. It will be demonstrated that various functional groups (such as alcohols, amines, enolates, and alkanes among others) can be efficiently oxidized. These oxidations can be carried out using nitroxides as catalysts in combination with various stoichiometric terminal oxidants. By reducing nitroxides to their corresponding anions, they become effective reducing reagents with intriguing applications in organic synthesis. Nitroxides possess the ability to selectively react with transient radicals, making them useful for terminating radical cascade reactions by forming alkoxyamines. Depending on their structure, alkoxyamines exhibit weak C−O bonds, allowing for the thermal generation of C radicals through reversible C−O bond cleavage. Such thermally generated C radicals can participate in various radical transformations, as discussed toward the end of this review. Furthermore, the application of this strategy in natural product synthesis will be presented.

show abstract

Section: Nitroxides In Free-radical Chemistrymentioning

confidence: 99%

Organic Synthesis Using Nitroxides

Leifert

Studer

2023

Chem. Rev.

View full text Add to dashboard Cite

show abstract

“…Because of the resonance of the carboxyl proton between its two oxygen atoms, the carboxyl group usually exhibits a low reactivity, making it uncommon for carboxylic acids to directly participate in reactions [14]. For example, it is difficult for α,β-unsaturated carboxylic acids to undergo the Michael addition, which often readily occurs for α,β-unsaturated carbonyl compounds [15][16][17][18][19][20][21]. Therefore, exploitation of the surrogates of carboxylic acid is, and will continue to be, highly desirable.…”

Section: Introductionmentioning

confidence: 99%

Progress in Catalytic Asymmetric Reactions with 7-Azaindoline as the Directing Group

Zhang,

You,

Yin

et al. 2023

Molecules

View full text Add to dashboard Cite

α-Substituted-7-azaindoline amides and α,β-unsaturated 7-azaindoline amides have emerged as new versatile synthons for various metal-catalyzed and organic-catalyzed asymmetric reactions, which have attracted much attention from chemists. In this review, the progress of research on 7-azaindoline amides in the asymmetric aldol reaction, the Mannich reaction, the conjugate addition, the 1,3-dipole cycloaddition, the Michael/aldol cascade reaction, aminomethylation and the Michael addition-initiated ring-closure reaction is discussed. The α-substituted-7-azaindoline amides, as nucleophiles, are classified according to the type of α-substituted group, whereas the α,β-unsaturated 7-azaindoline amides, as electrophiles, are classified according to the type of reaction.

show abstract

Recent Advances in the Synthesis of Pyrrolidines

Hosseininezhad,

Ramazani

2024

Heterocyclic Chemistry - New Perspectives

View full text Add to dashboard Cite

The pyrrolidine ring is one of the important and valuable heterocyclic compounds. This five-membered ring containing nitrogen is also known as tetrahydropyrrole. This heterocyclic scaffold is present in medicinal and biological molecules as well as bioactive compounds and alkaloids because of the properties and characteristics of this ring. Considering the sensitivity of the subject and the importance of this structure, the recent advances in the synthesis of these types of structures are very important. In this chapter, we reviewed the recent advances in the synthesis of pyrrolidines along with the mechanisms and limitations, with a detailed discussion from 2019 to 2023.

show abstract

A Diastereoselective Catalytic Approach to Pentasubstituted Pyrrolidines by Tandem Anionic‐Radical Cross‐Over Reactions

Cited by 3 publications

References 57 publications

Organic Synthesis Using Nitroxides

Organic Synthesis Using Nitroxides

Progress in Catalytic Asymmetric Reactions with 7-Azaindoline as the Directing Group

Recent Advances in the Synthesis of Pyrrolidines

Contact Info

Product

Resources

About