C-radicals

Fig, H8. (a) Partial rale factors of free radical phenylation, relative to benzene (397). (b) Free valence calculated by HMO method (117). (c) Radical localization energy (in units) calculated by HMO method (117). 

Bevingion, J.C. Radical Polymerization Academic Press London, 1961. 

Perhaps the most characteristic property of the carbon-carbon double bond is its ability readily to undergo addition reactions with a wide range of reagent types. It will be useful to consider addition reactions in terms of several categories (a) electrophilic additions (b) nucleophilic additions (c) radical additions (d) carbene additions (e) Diels-Alder cycloadditions and (f) 1,3-dipolar additions. 

The synthesis of a-substituted phosphonates 89, via the electrophilic addition of phosphorylated C-radicals 88 (generated by reaction of BujSnH to the readily accessible a-phosphoryl sulfides (or selenides)) and electrophilic addition to electron rich alkenes, has been described [57] (Scheme 26). A large excess of alkene is necessary to minimize the competitive formation of the undesired compound 90 resulting from direct reduction of the initial radical 88. The ratio 89/90 has been measured for each example. The synthesis of the a-mono- or a,a-di-substituted (R or phosphonates 89 shows that the free radical approach... 

Landolt-Bornstein. In H. Fischer, (ed.) Numerical Data and Functional Relationships in Science and Technology, New Series, Group II Atomic and Molecular Physics, vol 13, subvol c, Radical Reaction Rates in Liquids, Berlin Springer-Verlag, 1984. 

I. Addition of C-Radicals to Nitrones Recently (525), the addition of alkyl radicals to chiral nitrones as a new method of asymmetrical synthesis of a-amino acids has been described. Addition of ethyl radicals to glycosyl nitrone (286) using Et3B as a source of ethyl radicals appears to proceed with a high stereo-control rate. 

Alternatively, the C radical can abstract H from Cl in a five-membered TS to give the cyclobutanone, CO, and PhCHO. 

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