N‐Oxyl Radicals in Oxidative C–O Coupling: Free‐Radical Hydrogen Substitution and Addition to C=C Bonds DOI
Elena R. Lopat’eva, Igor B. Krylov, Bing Yu

et al.

Asian Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 18, 2024

Abstract N ‐oxyl radicals occupy an important place in free‐radical oxidative CH‐functionalization being one of the most efficient redox‐organocatalysts for hydrogen atom abstraction (HAT). Their applications include aerobic radical chain autoxidation, with formation carbon‐carbon and carbon‐heteroatom bonds. The persistent nature N‐ oxyl combined their high reactivity HAT results unique dual chemistry: same can both propagate reaction (at low concentrations) effectively “terminate” carbon‐centered higher concentrations). latter case opens a new synthetic application area radicals, which they act as abstracting species O‐reagents cross‐coupling thus produced. Apart from C−H bond cleavage, reactive have been extensively used recently C=C double functionalization via addition reactions. In this review, reactions introduction fragments alkene difunctionalizations by oxyls are covered emphasis on relationship between conditions selectivity.

Language: Английский

Organic Synthesis Using Nitroxides DOI
Dirk Leifert, Armido Studer

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

Citations

77
Access to chiral β-amino sulfones from acrylamides and sulfur dioxide by iron catalysis DOI
Liping Luo, Xuemei Zhang,

Chunxi Huang

et al.

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(6), P. 1678 - 1684

Published: Jan. 1, 2024

This method allows for the enantioselective synthesis of β-azide sulfones via iron-catalyzed vicinal azide-sulfonylation acrylamides. It makes first instance achieving asymmetric construction through iron catalysis with SO 2 insertion.

Language: Английский

Citations

5
Generation of perthiyl radicals for the synthesis of unsymmetric disulfides DOI Creative Commons

Fei Zhou,

X. He, Mi Zhou

et al.

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Jan. 2, 2025

Unsymmetric disulfides are prevalent in natural products and essential medicinal chemistry materials science, but their robust synthesis poses significant challenges. In this paper, we report an expeditous transition-metal-free methodology for synthesizing unsymmetric through the addition of perthiyl radicals to alkenes. This study marks use generating by reacting SO2 with unactivated alkyl (pseudo)halides (Cl/Br/I/OTs). Various primary, secondary tertiary substituted different functional groups successfully function as suitable reactants. The formation involvement reaction process verified mechanistic studies DFT calculations. Overall, method leverages readily available electrophiles alkenes alongside a single setup efficiently form both carbon-sulfur sulfur-sulfur bonds simultaneously. Here, authors novel transition-metalfree

Language: Английский

Citations

0
Transition-Metal-Catalyzed Regiodivergent Sulfonylation of Aziridrines for the Synthesis of β‑Amino Sulfones DOI

Qinqiong Zeng,

Yujia Gong,

X. He

et al.

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(22), P. 6340 - 6346

Published: Jan. 1, 2024

We developed the first transition-metal-catalyzed, regiodivergent sulfonylation of aziridines, enabling efficient synthesis diverse β-amino sulfones under mild conditions with broad substrate compatibility and high regioselectivity.

Language: Английский

Citations

3
Organophotocatalytic Three‐Component Assembly of C4‐Cyanoalkylated Phthalazin‐1(2H)‐Ones DOI Open Access

Poornima Mishra,

Ruchir Kant,

Namrata Rastogi

et al.

Chemistry - An Asian Journal, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 14, 2025

Abstract The present work documents construction of C4‐cyanoalkylated phthalazinones under visible light‐mediated conditions. three‐component reaction involving aryl hydrazines, 2‐formylbenzoic acids and cyclobutanone oxime esters with organic dye Eosin Y as photocatalyst, features initial formation subsequent cyanoalkylation phthalazin‐1(2H)‐one in one pot. is notable for mild conditions, operational simplicity, wide substrate scope good yields the products. phthalazinone products were further converted into other valuable derivatives.

Language: Английский

Citations

0
DABCO‐Mediated Photoelectrochemical Three‐Component Sulfonocyclization of 3‐Aza‐1,5‐dienes DOI

Lu-Cai Ding,

Gui-Hong Yang,

Li Luo

et al.

Chinese Journal of Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 2, 2024

Comprehensive Summary Herein, we report a rare example of three‐component net‐oxidative sulfonylation SO 2 surrogate with an oxidatively activated radical precursor under mild and metal‐ external‐oxidant‐free conditions. The mildness sustainability the reaction are enabled by photoelectrocatalysis, 3‐aza‐1,5‐dienes, organotrifluoroborates 1,4‐diazabicyclo[2.2.2]octane bis(sulfur dioxide) adduct (DABSO) undergo sulfonylative cyclization to afford sulfono 4‐pyrrolin‐2‐ones in atom‐economical manner broad substrate scope good functional‐group tolerance. protocol is amenable late‐stage diversification complex molecular architectures as well gram‐scale synthesis. Sunlight could be used light source, conducted all‐solar mode using commercially available photovoltaic panel generate electricity situ . Mechanistic studies reveal that generated (DABCO), which was generally innocent previous reactions, functions electron shuttle between photocatalytic cycle reactants.

Language: Английский

Citations

2
The diacetyliminoxyl radical in oxidative functionalization of alkenes DOI
Alexander S. Budnikov, Igor B. Krylov,

Andrey V. Lastovko

et al.

Organic & Biomolecular Chemistry, Journal Year: 2023, Volume and Issue: 21(38), P. 7758 - 7766

Published: Jan. 1, 2023

The intermolecular oxime radical addition to CC bonds was observed and studied for the first time. diacetyliminoxyl proposed as a model reagent study of reactivity towards unsaturated substrates, which is important in light active development synthetic applications radicals. In present work it found that reacts with vinylarenes conjugated dienes give products, whereas unconjugated alkenes can undergo or allylic hydrogen substitution by depending on substrate structure. Remarkably, substituted high yields C-O coupling products despite significant steric hindrance, unsubstituted lower products. atypical yield dependence alkene structure explained discovered ability attack formation C-N bond instead giving side This process not expected sterically hindered due availability N-atom than O-atom.

Language: Английский

Citations

4
Recent advances in ring-opening of cyclobutanone oximes for capturing SO2, CO or O2via a radical process DOI
Long‐Jin Zhong, Jian‐Hong Fan, Pu Chen

et al.

Organic & Biomolecular Chemistry, Journal Year: 2023, Volume and Issue: 22(1), P. 10 - 24

Published: Nov. 23, 2023

In this review, we conclude recent main themes in trapping SO 2 , CO or O by cyanoalkyl radicals, which are produced from iminyl-radical-triggered C–C bond cleavage of cyclobutanone oxime derivatives.

Language: Английский

Citations

3
Copper-catalyzed sulfonamidation of enol silyl ether via SO2 insertion towards the synthesis of β-keto sulfonamides DOI

Qinqiong Zeng,

Yujia Gong,

Xuemei Zhang

et al.

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(13), P. 3589 - 3595

Published: Jan. 1, 2024

This method offers a simple, effective pathway for synthesizing diverse β-keto sulfonamides with satisfactory yields under mild conditions, showing broad substrate compatibility and good tolerance towards various functional groups.

Language: Английский

Citations

0
Brønsted base catalyzed Reppe sulfonylation reaction DOI
X. He, Xiaohong Wang, Fei Zhou

et al.

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(17), P. 4740 - 4747

Published: Jan. 1, 2024

The Reppe sulfonylation reaction has remained substantially underexplored. We present a novel method for involving SO 2 insertion, remarkably without the need metal catalysts, instead utilizing Brønsted bases as catalysts.

Language: Английский

Citations

0