Chemical synthesis of 6-deoxy- d -talose containing a tetrasaccharide repeating unit of the O-specific polysaccharide from Enterobacter cloacae G3422 in the form of its 2-aminoethyl glycoside

G3422 is reported. The synthesis of the target tetrasaccharide is achieved through a convergent [2 + 2]-block strategy. The conjugation ready target oligosaccharide is attractive for further glycoconjugate formation with a suitable aglycon. Synthesis of the challenging 6-deoxy-L-talose moiety is reported using two different approaches and the obvious difficulties are discussed.