Reaction of Thianthrene Cation Radical with Diarylmercurials. Search for Single Electron Transfer Is Elusive

1993 ◽  
Vol 58 (1) ◽  
pp. 82-88 ◽  
Author(s):  
A. K. M. M. Hoque ◽  
Henry J. Shine ◽  
T. Krishnan Venkatachalam
Keyword(s):  
Electron Transfer ◽  
Cation Radical ◽  
Product Formation ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Aryl Radicals ◽  
Stoichiometric Ratios

Diarylmercurials (Ar2Hg) with Ar = p-tolyl Ib, o-tolyl Ic, p-anisyl Id and 2-allyloxy-4,5-dimethylphenyl Ie, reacted with thianthrene cation radical perchlorate (Th.+ClO4-) in two stoichiometric ratios: 2 : 1 and 4 : 1 (Th.+ClO4-/Ar2Hg). In the 2 : 1 ratio the products were the 5-arylthianthreniumyl perchlorates IIb - IIe, thianthrene (Th) and ArHg+ClO4- (assayed as ArHgCl, III) in quantitative yields. In the 4 : 1 ratio reaction with ArHg+ occurred, too, and the products were IIb - IIe, Th, the complex Th3Hg(ClO4)2 and HgO (after workup). In contrast, Ph2Hg (Ia) did not react beyond the 2 : 1 stoichiometry. In the reactions with Ie, no evidence for formation and cyclization of free 2-allyloxy-4,5-dimethylphenyl radical was found. Reaction of and product formation from these arylmercurials, therefore, does not occur in single electron transfer steps that lead to free aryl radicals. Instead electron transfer appears to occur within a complex of Ar2Hg with Th.+ from which II and other products are subsequently formed.

scholarly journals Intermolecular oxyarylation of olefins with aryl halides and TEMPOH catalyzed by the phenolate anion under visible light

2020 ◽  
Vol 11 (27) ◽  
pp. 6996-7002
Author(s):  
Kangjiang Liang ◽  
Qian Liu ◽  
Lei Shen ◽  
Xipan Li ◽  
Delian Wei ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Aryl Halides ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Strong Reduction ◽  
Aryl Radicals ◽  
Reduction Potentials

The phenolate anion was developed as a new photocatalyst with strong reduction potentials (−3.16 V vs. SCE) to reduction of aryl halides to aryl radicals through single electron transfer.

scholarly journals Alcohol-Initiated Dediazoniation of Aryldiazonium Ions to Aryl Radicals: A Simple and Efficient Route to Arylboronates

2018 ◽  
Vol 42 (9) ◽  
pp. 481-485
Author(s):  
Xiulian Zhang ◽  
Zhicheng Zhang ◽  
Yongbin Xie ◽  
Yujie Jiang ◽  
Ruibo Xu ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Bond Formation ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Aryl Radical ◽  
Radical Species ◽  
Aryl Radicals ◽  
Efficient Access ◽  
Efficient Route ◽  
Operational Simplicity

A simple and efficient access to arylboronates was achieved with methanol-initiated borylation of aryldiazonium salts. Reduction of aryldiazonium ions by single electron transfer from methanol affords aryl radical species, which undergo a subsequent C–B bond formation with bis(pinacolato)diboron. This highly practical borylation process, which can be carried out on the gram-scale, enjoys operational simplicity as well as mild and catalyst-free conditions.

Effect of alkyl group length on the conductivity in the 2,3,7,8,12,13,17,18-octakis(alkyl-thio)tetraazaporphyrins and redox properties of the metallooctakis(hexyl-thio)tetraazaporphyrins

2002 ◽  
Vol 06 (07) ◽  
pp. 447-455
Author(s):  
Bin Yu ◽  
Yanxiu Zhou ◽  
Daike Wang ◽  
Zhenxing Wang ◽  
Kenichi Sugiura ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Cation Radical ◽  
Differential Pulse ◽  
Single Electron ◽  
Central Metal Atom ◽  
Central Metal ◽  
Single Electron Transfer ◽  
Electron Transfer Pathways ◽  
Chain Lengths

A series of 2,3,7,8,12,13,17,18-octakis(alkyl-thio)tetraazaporphyrins (H2OATTAP) with different alkyl chain lengths have been synthesized. Cyclic voltammetry and differential pulse voltammetry have been used to investigate the effect of the controlled lengths of the eight peripheral thioether tails on the redox behavior of the molecules. The electrochemical reduction of octakis(hexyl-thio)tetraazaporphyrins, MOHTTAP (where M = Cu , Ni ), was studied in 1,2-dichloroethane at a platinum electrode. The Cu derivative was oxidized in one single-electron-transfer step to yield a π-cation radical and reduced in three single-electron-transfer steps to yield a π-anion radical, dianion and trianion, respectively. For the Ni derivative, electron transfer reactions involving both the central metal atom and the macrocyclic ring were observed. Electron transfer pathways are proposed based upon voltammetric and in situ spectroelectrochemical results.

scholarly journals Aryl radical-mediated N-heterocyclic carbene catalysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuki Matsuki ◽  
Nagisa Ohnishi ◽  
Yuki Kakeno ◽  
Shunsuke Takemoto ◽  
Takuya Ishii ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Single Electron ◽  
Radical Reactions ◽  
Single Electron Transfer ◽  
Aryl Radical ◽  
Aryl Iodide ◽  
Alkyl Radicals ◽  
Aryl Radicals ◽  
Electron Transfer Processes ◽  
Secondary Amides

AbstractThere have been significant advancements in radical reactions using organocatalysts in modern organic synthesis. Recently, NHC-catalyzed radical reactions initiated by single electron transfer processes have been actively studied. However, the reported examples have been limited to catalysis mediated by alkyl radicals. In this article, the NHC organocatalysis mediated by aryl radicals has been achieved. The enolate form of the Breslow intermediate derived from an aldehyde and thiazolium-type NHC in the presence of a base undergoes single electron transfer to an aryl iodide, providing an aryl radical. The catalytically generated aryl radical could be exploited as an arylating reagent for radical relay-type arylacylation of styrenes and as a hydrogen atom abstraction reagent for α-amino C(sp3)–H acylation of secondary amides.

Reversal of Polarity by Catalytic SET Oxidation: Synthesis of Azabicyclo[m.n.o]alkanes via Chemoselective Reduction of Amidines

2021 ◽  
Author(s):  
Sundarababu Baskaran ◽  
Kirana D V ◽  
Kanak Kanti Das
Keyword(s):  
Electron Transfer ◽  
Stereoselective Synthesis ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Catalytic Method ◽  
One Pot ◽  
Oxidative System ◽  
Oxidation Synthesis

A one-pot catalytic method has been developed for the stereoselective synthesis of cyclopropane-fused cyclic amidines using CuBr2/K2S2O8 as an efficient single electron transfer (SET) oxidative system. The generality of this...

Sign in / Sign up

Export Citation Format

Share Document