An electrochemical aromatic chlorination, comparison with electrophilic reaction

Appelbaum, L.; Danovich, David; Lazanes, G.; Michman, M.; Oron, Miriam

doi:10.1016/s0022-0728(00)00465-4

Cited by 14 publications

(6 citation statements)

References 16 publications

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“…Electrochemical oxidation , serves as a powerful method for functionalize C–H bonds of aromatic compounds by the intermediacy of radical cations . Recently, we developed an effective method for the metal- and chemical-oxidant-free C–H/C–H cross-coupling of two aromatic compounds using the “radical-cation-pool” method …”

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confidence: 99%

Electrochemical C–H Amination: Synthesis of Aromatic Primary Amines viaN-Arylpyridinium Ions

2013

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We have developed a new method for C-H amination of aromatic compounds based on electrochemical oxidation of aromatic compounds in the presence of pyridine followed by the reaction of the resulting N-arylpyridinium ions with an alkylamine. This new transformation serves as a powerful method for synthesizing aromatic primary amines from aromatic compounds without using metal catalysts and harsh chemical reagents. High chemoselectivity of the present method is demonstrated by C-H amination of aromatic compounds bearing a nitro group to give a key intermediate for the synthesis of VLA-4 antagonist.

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confidence: 99%

Electrochemical C–H Amination: Synthesis of Aromatic Primary Amines viaN-Arylpyridinium Ions

2013

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“…With the catalyst removed from the solution, selectivity is obtained. A detailed report is not reiterated here, but in fact this electrochemical procedure in an undivided cell yielded just two monochlorinated products and the tert -butyl group is preserved, even at 80% completion of the reaction (Figure ). The possibility of such simple complementary control using a counter electrode is an exclusive asset of the electrochemical method.…”

Section: Resultsmentioning

confidence: 99%

“…Compounds also formed in small amounts: 3-chloro-1,4-dimethoxybenzene ( 6 ); 2,3,5-trichloro-1,4-dimethoxybenzene ( 7 ); 2- tert -butyl-3,5,6-trichloro-1,4-dimethoxybenzene ( 8 ). Reproduced with permission from ref .…”

Section: Resultsmentioning

confidence: 99%

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Homogeneous Catalysis and Selectivity in Electrochemistry

et al. 2014

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The relationship between homogeneous catalysis and electrochemistry is examined in light of two examples based on our work concerning (a) catalyst activation, regarding selective electrochemical C−H oxidation with Ru III /Ru IV mediation, and (b) catalyst suppression, regarding controlling selectivity in electrochemical aromatic chlorination. The first example (a) deals with the role of catalysis at the working electrode. The electrochemical (EC) oxidation of specific hydrocarbons such as tetralin and indane is performed using tris(acetonitrile)ruthenium trichloride (Ru(CH 3 CN) 3 Cl 3 ) as a mediator. The role of this mediator in the oxidation of tetralin has been reported. This homogeneous C−H activation by electron transfer (ET) is accompanied by the redox transitions of the mediator in the course of the catalytic oxidation, and these are the main points of interest here. Additional studies with a rotating ring disk electrode (RRDE) provided a follow-up of creation and recovery of Ru III /Ru II and Ru III /Ru IV species in the process. Using electrochemistry linked with electrospray ionization mass spectrometry (EC/ESI-MS) gave additional information on the structure of the reduced and oxidized forms of Ru(CH 3 CN) 3 Cl 3 and the effect of water in the solvent on their lifetimes. The second example (b) of electrochlorination has been reported elsewhere and is brought up as complementary remarks. Aromatic electrophilic chlorination of 1,4-dimethoxy-2-tertbutylbenzene is autocatalyzed and unselective. The EC procedure provides a simple means to inhibit the catalytic runaway reaction. This example shows how the counter electrode affects catalysis and selectivity.

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“…356 In contrast to the electrochemical fluorination strategies, the anodic oxidation protocols involving chlorides, bromides and iodides typically proceed via generation of the corresponding electrophilic molecular counterpart (X 2 ) due to the relatively low oxidation potentials of these halogen ions. [357][358][359][360][361][362][363][364][365][366][367] Due to the limited solubility of alkali metal halide salts in organic solvents, a biphasic system consisting of an aqueous phase and a halogenated organic solvent is commonly employed to affect chlorination of aromatics 368,369 and heterocycles 370 as well as bromination of toluene derivatives. 371 The electrodes are placed in the upper layer of the aqueous phase, thus enabling selective oxidation of the halide.…”

Section: Anodic Halogenationmentioning

confidence: 99%

Electrochemical strategies for C–H functionalization and C–N bond formation

2018

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Conventional methods for carrying out carbon-hydrogen functionalization and carbon-nitrogen bond formation are typically conducted at elevated temperatures, and rely on expensive catalysts as well as the use of stoichiometric, and perhaps toxic, oxidants. In this regard, electrochemical synthesis has recently been recognized as a sustainable and scalable strategy for the construction of challenging carbon-carbon and carbon-heteroatom bonds. Here, electrosynthesis has proven to be an environmentally benign, highly effective and versatile platform for achieving a wide range of nonclassical bond disconnections via generation of radical intermediates under mild reaction conditions. This review provides an overview on the use of anodic electrochemical methods for expediting the development of carbon-hydrogen functionalization and carbon-nitrogen bond formation strategies. Emphasis is placed on methodology development and mechanistic insight and aims to provide inspiration for future synthetic applications in the field of electrosynthesis.

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An electrochemical aromatic chlorination, comparison with electrophilic reaction

Cited by 14 publications

References 16 publications

Electrochemical C–H Amination: Synthesis of Aromatic Primary Amines viaN-Arylpyridinium Ions

Electrochemical C–H Amination: Synthesis of Aromatic Primary Amines viaN-Arylpyridinium Ions

Homogeneous Catalysis and Selectivity in Electrochemistry

Electrochemical strategies for C–H functionalization and C–N bond formation

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