One-Pot Assembly of the Rare Sugar Containing Trisaccharide Repeating Unit of <i>Pseudomonas putida</i> TSh-18

Herein, we report the first total synthesis of the trisaccharide repeating unit of <i>Pseudomonas putida</i> TSh18, achieved through a one-pot glycosylation strategy. The synthesis addresses several challenges, including the synthesis of rare sugars d-Fuc<i>p</i>4N₃ and d-Qui<i>p</i>NAc4NAc, installation of consecutive 1,2-cis linkages, and a late-stage amide coupling. Access to d-Fuc<i>p</i>4N₃ was enabled for the first time by applying a double serial inversion approach. The synthesis was completed in 19 linear steps with an overall yield of 5.5%.