Reduction of Carbon-Centered Radicals by Electron Transfer

Reduction of Carbon-Centered Radicals by Electron Transfer 

In the reduction of radicals by ET, simple carbanions are practically never formed, and one-electron reduction of a carbon-centered radicals is only effective if the electron can be accommodated by the substituent, e.g., a carbonyl group [reaction (24), whereby upon electron transfer the enolate is formed (Akhlaq et al. 1987)]. Thus, in their reduction reactions these radicals react like heteroatom-centered radicals despite the fact that major spin density is at carbon. 

The mesomeric forms of the pyrimidine C(6)-adduct radicals may be written with the free spin at a heteroatom and hence have as oxidizing properties. 

Their yields have been determined with the help of a strong reductant, TMPD (Chap. 10.3). Other convenient probes for monitoring oxidizing radicals are, for example, ABTS and ascorbate (Wolfenden and Willson 1982 Bahnemann et al. 1983). 

Radical cations are especially strong oxidants, since they are highly electron deficient. They are intermediates in OH-induced DNA strand breakage and are capable of oxidizing a neighboring G (Chaps 12.4 and 12.9). 

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Reduction of Carbon-Centered Radicals by Electron Transfer 110 ... 

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