with DBU in acetonitrile to afford the product of elimination 21 in good yield (Scheme 5). The same chemistry was carried out on the d-manno and d-galacto derivatives which gave the analogous compounds in similar yields .
Work by Magnusson dealt with the application of allylic sulfones as radical acceptors for allylic carbon-carbon bond formation at the radical center. Various acceptors were utilized, and the products are shown in Scheme 6 .
The Kolbe electrolysis of sugar acids to give radicals and their subsequent trapping with a radical source gave the chain-extended C-glycoside 27 as the major product (Scheme 7). Compounds such as 27 are useful as stable nonionic tensides and are expected to show liquid crystalline properties .
Vismara, Nicotra, and their colleagues used glycoexenitol, 30 and 32 as radical acceptors in the preparation of precursors for isosteres of glycolipids and glycoproteins. In this case, the formed radical is anomeric, and reduction by tin hydride from the axial direction should then give the ^-C-glycoside. The additions proceeded cleanly to give only 31 and 33 as the major products of (a:fi = 10:4) noting that the yields
are quantitative when based on the amount of recovered glycoexenitol. Gervay has added thiolacetic acid to 32 to obtain 34 in good yield, (Scheme 8) .
Motherwell published the full paper corresponding to his initial work on radical additions to difluoromethylene-linked C-glycosides. Scheme 9 shows an application of the atom transfer work developed by Curran with iodide 34 to give the bis-C,C-dialkylglycoside in fair yield .
Fraser-Reid has published a full account of his work on serial radical cyclizations with carbohydrates. The example shown (38 ^ 40, Scheme 10) illustrates the complexity of the frameworks that can be accessed by careful application of this methodology .
Work by Beau, Skrydstrup, and their colleagues has focused on the generation of anomeric radicals from anomeric sulfones by treatment with samarium iodide . If a radical trap is present, the second electron transfer to form the C1 anion does not have time to occur to any appreciable extent, and the formed radical can then
Was this article helpful?
Top Low Carb Internet Guru Speaks Out. An Open Letter To Anyone Who Wants To Lose Up To 20 Pounds In 30 Days The 'Low Carb' Way. 30-Day Low Carb Diet 'Ketosis Plan' has already helped scores of people lose their excess pounds and inches faster and easier than they ever thought possible. Why not find out what 30-Day Low Carb Diet 'Ketosis Plan' can do for you by trying it out for yourself.