6-Deoxyheptoses in Nature, Chemistry, and Medicine

6-Deoxyheptoses are rare higher-carbon sugars isolated from lipopolysaccharides (LPS) and capsular polysaccharides (CPS) of some Gram-negative bacteria (Campylobacter, Yersinia, Burkholderia, Eubacterium, Plesiomonas, and Escherichia species). They occur in numerous structural variations of the bacterial polysaccharides (PS), which are briefly summarized. Biochemical pathways involving deoxygenation of heptoses as well as possible approaches towards the chemical synthesis of these unusual monosaccharides will be discussed. The most important methods for the preparation of 6-deoxyheptoses include elongation of pentose or hexose chains by nucleophilic substitution, Wittig-type reaction, and nucleophilic addition into carbonyl group.