There are several ways to introduce fluorine into carbohydrates. Some typical fluorinations are 1) the reaction of diethylaminosulfur trifluoride (DAST) or tetrabutylammonium fluoride (TBAF) with the hydroxyl or sulfonylated hydroxyl groups, respectively, 2) ring opening of the oxirane or epimine with the olah reagent or potassium hydrogen fluoride (KHF
2), 3) addition of fluoroxytrifluoromethane (CF
3OF), acetyl hypofluorite (CF
3CO
2F), or xenon difluoride (XeF
2) to the vinyl ethers (for example, glycals), 4) fluorination of carbonyl compounds with DAST or F-containing Wittig reagents, and 5) substitution of active groups by fluorine with appropriate reagents. For structural elucidation of the fluorinated carbohydrates,
19F-NMR spectroscopy gives a very useful tool by showing rather simple signal pattern in comparison to that of the
1H-NMR spectrum of the same compound. The
3J
H, F values, which vary greatly with the : change of the stereo- and electro-chemical environments, are also useful.
抄録全体を表示