Kdo Glycosylations and Their Application in Oligosaccharide Synthesis**

Abstract Higher carbon saccharide 3‐deoxy‐ d ‐ manno ‐oct‐2‐ulosonic acid (Kdo) is a structural unit of bacterial lipopolysaccharides (LPSs) and capsular polysaccharides (CPSs). Kdo is present in the inner core region of LPSs, and this region is structurally conserved. Being non‐mammalian in origin, Kdos are effectively recognized by the native and adaptive immune systems. Therefore, the synthesis of new Kdo derivatives and neoglycoconjugates is highly important for the development of vaccines. This review highlights recent accomplishments related to α ‐ glycosylations, β‐glycosylations and C‐glycosylations of Kdos and their application to the stereoselective synthesis of inner core oligosaccharides.