A Highly Practical Synthesis of Sulfated Lewis X: One-Pot, Two-Step Glycosylation Using "Armed/Disarmed" Coupling and Selective Benzoylation and Sulfation

In spite of the several attractive biological activities of the Le^x, sLe^x, and sulfated Le^x derivatives, there are still limitations in their practical syntheses. One of the most difficult problems is the many steps required for their syntheses. Therefore, we investigated simple constructions of the Le^x analogs and succeeded in establishing highly practical syntheses of the Le^x and sulfated Le^x analogs. Especially, the "armed/disarmed" method allowed the first synthesis of Le^x derivatives by a one-pot, two-step glycosylation. This synthetic strategy could be an applicable and useful method for oligosaccharide constructions of Le^x, sulfated Le^x, and other derivatives.