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Radical anions, as intermediates

The presence of radical anions as intermediates has been clearly established in many organic reactions and has been the subject of theoretical studies due to their importance in different types of organic reactions including DNA dam-agei8t,i82 jn these intermediates, the it-acceptor can be linked to the C-X bond... [Pg.98]

In this process, represented by equations 1-8 in Scheme 1, a substitution is achieved with radicals and radical anions as intermediates. According to this mechanistic proposal the radical anion of the substrate is formed in the initiation step (equation 1) by an electron transfer (ET) from a suitable electron source such as solvated electrons from dissolved alkaline metals, sodium amalgam, reducing agents such as Fe+2, Sml2, electrons from a cathode or by a negatively charged species (nucleophile) under thermal, sonication or photochemical stimulation. [Pg.1397]

Since the pioneering studies of Bunnett [3], the scope of the unimolecular radical nucleophilic substitution (SrnI) reaction has increased considerably, and today this approach is well established for the formation of aryl-carbon and aryl-heteroatom bonds. The SrnI reaction is a chain process which includes radicals and radical anions as intermediates the reaction mechanism is depicted in Scheme 13.1 [1]. [Pg.475]

The presence of radical anions as intermediates has been proposed in the reactions of 1,2-, 1,3-, or 1,4-dihalobenzenes with benzene, which are then converted into disubstituted products (o-, m-, and p-terphenyl, 133 Scheme 9.15) [110-112, 115]. Once the radical anion 130 is formed as the intermediate, it can follow two possible pathways. One of these is an intermolecular ET to give halobiphenyl 131 (monosubstituted product) (Path A). The other possibility is an intramolecular ET... [Pg.236]

For unactivated aromatic and heteroaromatic substrates, where a polar substitution is not favorable, nucleophilic substitution is feasible through processes that involve electron transfer (ET) steps. In these reactions, an aromatic compound bearing an adequate leaving group is substituted at the ipso position by a nucleophile in a unimolecular radical nucleophilic substitution mechanism (or S,y.jl), which is a chain process that involves radicals and radical anions as intermediates. [Pg.920]


See other pages where Radical anions, as intermediates is mentioned: [Pg.340]    [Pg.319]    [Pg.320]    [Pg.495]    [Pg.27]    [Pg.1395]    [Pg.1400]    [Pg.5202]    [Pg.906]    [Pg.1427]    [Pg.17]    [Pg.349]    [Pg.5201]    [Pg.76]    [Pg.105]    [Pg.91]    [Pg.133]    [Pg.99]   


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A Anionic

A radical anion

Anion radical intermediates

Intermediate anionic

Radical intermediates

Radicals as intermediates

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