Fluorinated disaccharides synthesis

The base-catalyzed addition of alcohols to nitriles to give imidates proceeds well, if there are electron-attracting groups in the a-position. In such cases the Pinner synthesis is less effective, because nitrile basicity is less. TTiis shows that both methods are complementary. Recently attention has been paid to the long-known addition of alcohols to trichloroacetonitrile, since it was found that imidates prepared from protected saccharides, amino alcohols etc. and trichloroacetonitrile are useful reagents for the synthesis of nucleosides, disaccharides and other natural products. The trichloroacetimidic acid esters (240 equation 131) of fluorinated, unsaturated aliphatic alcohols °° and benzyl alcohol have been prepared for synthetic purposes. 

Disaccharide anthracyclines were synthesized, in which the daunosaraine moiety is separated from the aglycone by either a rhamnose or fucose residue. Fluorine was reported on the fucose moiety (70) [89] and on the aglycone at C-8 (71) [20] (Fig. 11). Both examples indicate two important considerations first, anthracyclines, with an activity comparable to that of DOXO, possess the daunosamine moiety not directly linked to the aglycone second, the fluorine does not lower the activity of these compounds but allows the synthesis of new derivatives with a particularly high activity in inhibiting the growth of cultured human tumor cells. 

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