In conclusion, we have successfully completed the first total synthesis of zwitterionic trisaccharide repeating unit of Fusobacterium nucleatum ATCC 51191 O-antigen. Our synthesis involves use of Cbz protecting group in AAT building block which serves a dual purpose for temporary masking of the C4-amino function and for achieving 1,2-cis selectivity with isopropanol. A late stage amide bond formation of trisaccharide and early stage oxidation at monosaccharide level facilitated expeditious assembly of the target molecule. The efficient synthesis was completed via a longest linear sequence of 22 steps in 2.3% overall yield. The synthetic strategy also enabled total synthesis of other frame shift trisaccharides and longer oligomers. The biological studies using these glycans are currently underway in Silipo laboratory.