Carbon-modified sugars: from natural products to glycomimetics

Bacteria take prototypical aldohexopyranoses and remodel them into more elaborate sugars that provide them advantages in competitive environments. The attachment of alkyl or acyl units directly onto carbons of the hexose backbone is one means of that transformation of "normal" sugars to the novel ones. Similarly, the incorporation of alkyl, vinyl, and aryl groups directly onto hexose carbons is a structural feature used in the design of glycomimetic compounds. These can collectively be classified as carbon-modified sugars. A survey of synthetic methods used to prepare carbon-modified sugars is presented here, along with examples of how they have been used to address questions in carbohydrate chemistry and biochemistry. The strategy is given context by considering the functions and the biosynthesis of some example bacterial sugars bearing carbon modifications. The upshot is a call for additional fundamental investigations on this class of carbohydrate analogs and their broader application in biological and medicinal chemistry.