Synthesis of a tetrasaccharide corresponding to the teichoic acid from the cell wall of Streptomyces sp. VKM Ac-2275

A concise chemical synthesis of a tetrasaccharide found in the teichoic acid from the cell wall of Streptomyces sp. VKM Ac-2275 was achieved in high yield. A [2+2] block synthetic strategy has been adopted for the construction of the target tetrasaccharide by exploiting the orthogonal property of a thioglycoside. For the first time, the 2-(4-methoxyphenoxy) ethyl group has been used as the anomeric protecting group to make the glycone moiety with a readily available linker for its conjugation to a protein without destroying the cyclic structure at the reducing end. Yields were high in all of the intermediate steps.