Substitution Reactions of Nitrothiophens. III. Radical and Ionic Reactions of 4- and 5-Nitro-2-thienyl-methyl and -ethyl Chlorides and Acetates

1979 ◽  
Vol 32 (12) ◽  
pp. 2647 ◽  
Author(s):  
PJ Newcombe ◽  
RK Norris
Keyword(s):  
Electron Transfer ◽  
Nucleophilic Attack ◽  
Coupling Reactions ◽  
Substitution Reactions ◽  
Radical Coupling ◽  
Ionic Substitution ◽  
Substitution Process ◽  
Nitro Derivatives ◽  
Srn1 Reaction ◽  
Coupling Processes

The reactions of 4-nitro-2-thienyl-methyl and -ethyl chlorides and acetates with lithium 2-nitropropan-2-ide (1) give excellent yields of the C-alkylates, 2-(2-methyl-2-nitropropyl)- and 2-(1,2-dimethyl-2-nitropropyl)-4-nitrothiophen. These reactions proceed by a novel ionic substitution process involving initial nucleophilic attack on the thiophen ring. The 5-nitro derivatives react to give complex mixtures of products, which arise from SRN1, SN2, elimination, electron transfer and radical coupling processes. For example, 2-(1-chloroethyl)-5-nitrothiophen (23) reacts with the salt (1) under nitrogen to give the C-alkylate, 2-(1,2-dimethyl-2-nitropropyl)-5-nitrothiophen (24), formedby an SRN1 reaction, the alkene, 2-(1,2-dimethylprop-1-enyl)-5-nitrothiopen (25), derived from (24) by elimination of nitrous acid, 1-(5-nitro-2-thienyl)ethanone (26) and 1-(5-nitro-2-thienyl)ethanol(27) produced by SN2 O-alkylation, and 2,2'-(1,2-dimethylethene-1,2-diyl)bis(5-nitrothiophen) (28) formed by electron transfer and radical coupling reactions.

On the Determination and Use of Reduction Potentials of Short-Lived Radicals. A Review

2000 ◽  
Vol 65 (6) ◽  
pp. 829-843 ◽  
Author(s):  
Henning Lund ◽  
Karen Skov ◽  
Steen Uttrup Pedersen ◽  
Torben Lund ◽  
Kim Daasbjerg
Keyword(s):  
Aqueous Solution ◽  
Electron Transfer ◽  
Reaction Mechanisms ◽  
Nucleophilic Attack ◽  
Grignard Reaction ◽  
Hydroxide Ion ◽  
Reduction Sequence ◽  
Reduction Potentials ◽  
Srn1 Reaction

A method, the "competition method", for the determination of reduction potentials and estimation of standard potentials for short-lived radicals is reviewed. Applications of the reduction potentials of radicals as arguments for reaction mechanisms are presented for the Grignard reaction, the photoreduction of ketones with alcohols, and the SRN1 reaction. Reductions induced by hydroxide ions are discussed in more detail, and the classic reaction between nitrosobenzene and hydroxide ion in aqueous solution is used as an example of such a reaction. A nucleophilic attack by hydroxide ion rather than an electron transfer initiates the reduction sequence. A review with 26 references.

scholarly journals Evidence of single electron transfer from the enolate anion of an N,N′-dialkyldiketopiperazine additive in BHAS coupling reactions

2017 ◽  
Vol 15 (41) ◽  
pp. 8810-8819 ◽  
Author(s):  
Katie J. Emery ◽  
Tell Tuttle ◽  
John A. Murphy
Keyword(s):  
Electron Transfer ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Coupling Reactions ◽  
Aromatic Substitution ◽  
Substitution Reactions ◽  
Homolytic Aromatic Substitution ◽  
Enolate Anion

A designed N,N′-dialkyldiketopiperazine (DKP) provides evidence for the role of DKP additives as initiators that act by electron transfer in base-induced homolytic aromatic substitution reactions, involving coupling of haloarenes to arenes.

scholarly journals Autocatalytic photoredox Chan-Lam coupling of free diaryl sulfoximines with arylboronic acids

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cong Wang ◽  
Hui Zhang ◽  
Lucille A. Wells ◽  
Tian Liu ◽  
Tingting Meng ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Hydrogen Atom Abstraction ◽  
Coupling Reactions ◽  
Ambient Light ◽  
Environmental Friendliness ◽  
Copper Species ◽  
Arylboronic Acids ◽  
Ligand Free ◽  
Byproduct Formation ◽  
Electron Reduction

AbstractN-Arylation of NH-sulfoximines represents an appealing approach to access N-aryl sulfoximines, but has not been successfully applied to NH-diaryl sulfoximines. Herein, a copper-catalyzed photoredox dehydrogenative Chan-Lam coupling of free diaryl sulfoximines and arylboronic acids is described. This neutral and ligand-free coupling is initiated by ambient light-induced copper-catalyzed single-electron reduction of NH-sulfoximines. This electron transfer route circumvents the sacrificial oxidant employed in traditional Chan-Lam coupling reactions, increasing the environmental friendliness of this process. Instead, dihydrogen gas forms as a byproduct of this reaction. Mechanistic investigations also reveal a unique autocatalysis process. The C–N coupling products, N-arylated sulfoximines, serve as ligands along with NH-sulfoximine to bind to the copper species, generating the photocatalyst. DFT calculations reveal that both the NH-sulfoximine substrate and the N-aryl product can ligate the copper accounting for the observed autocatalysis. Two energetically viable stepwise pathways were located wherein the copper facilitates hydrogen atom abstraction from the NH-sulfoximine and the ethanol solvent to produce dihydrogen. The protocol described herein represents an appealing alternative strategy to the classic oxidative Chan-Lam reaction, allowing greater substrate generality as well as the elimination of byproduct formation from oxidants.

Room-Temperature, Water-Promoted, Radical-Coupling Reactions of Phenols with tert-Butyl Nitrite

Synlett ◽  
2017 ◽  
Vol 28 (16) ◽  
pp. 2153-2156 ◽  
Author(s):  
Wen-Ting Wei ◽  
Hongze Liang ◽  
Wen-Ming Zhu ◽  
Weida Liang ◽  
Yi Wu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Phenol Derivative ◽  
Tert Butyl ◽  
Radical Coupling ◽  
Air Atmosphere ◽  
Cross Coupling Reaction ◽  
Temperature Water

A radical–radical cross-coupling reaction of phenols with tert-butyl nitrite has been developed with the use of water as an additive. This method allows the construction of C–N bonds under an air atmosphere at room temperature, providing the ortho-nitrated phenol derivative in moderate to good yields.

Via Radical Coupling Reactions

2003 ◽  
pp. 1
Author(s):  
E. P. Kündig ◽  
S. H. Pache
Keyword(s):  
Coupling Reactions ◽  
Radical Coupling

Polydopamine-embedded Cu2−xSe nanoparticles as a sensitive biosensing platform through the coupling of nanometal surface energy transfer and photo-induced electron transfer

The Analyst ◽  
2015 ◽  
Vol 140 (12) ◽  
pp. 4121-4129 ◽  
Author(s):  
Hong Yan Zou ◽  
Peng Fei Gao ◽  
Ming Xuan Gao ◽  
Cheng Zhi Huang
Keyword(s):  
Electron Transfer ◽  
Energy Transfer ◽  
Surface Energy ◽  
Surface Energy Transfer ◽  
Photo Induced Electron Transfer ◽  
Coupling Processes

This study innovatively highlights the mechanistic details of NSET and PET (NSET©PET) coupling processes, and the disclosed mechanism provides new opportunities for sensitive biosensing applications.

scholarly journals Photoinduced three-component coupling reactions of electron deficient alkenes, dienes and active methylene compounds

2018 ◽  
Vol 17 (8) ◽  
pp. 1118-1126 ◽  
Author(s):  
Hajime Maeda ◽  
Hiroshi Takayama ◽  
Masahito Segi
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Coupling Reactions ◽  
Active Methylene Compounds ◽  
Active Methylene ◽  
Three Component Coupling

In this effort, we developed novel three component coupling reactions of electron deficient alkenes, dienes and active methylene compounds via photoinduced electron transfer.

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