Fluorine-containing carbohydrates are used as biological probes to study various biological processes (especially carbohydrate-protein interactions). The fluorine substituent is the optimal bioisostere of the hydroxy group because of its size, stability, and its ability to accept hydrogen-bond. Despite increased interest in the preparation of fluoro sugars, the introduction of the fluorine atom into some sugar moieties can still be a challenge. Diethylaminosulfur trifluoride (DAST)-mediated fluorination and the two-step nucleophilic substitution of leaving groups with a fluoride-ion are the most common approaches to fluorinated carbohydrates. In addition, linear de novo methodologies are also used for the preparation of fluorine-containing carbohydrates but are less attractive due to their longer synthetic sequences. In this context, the pioneering work of Linclau's group for the synthesis of heavily fluorinated monosaccharides as substrates for enzymatic reactions is also worth noting.
