Immunomodulating glycosphingolipids: an efficient synthesis of a 2′-deoxy-α-galactosyl-GSL

A new and efficient approach to the total synthesis of 2′-deoxy-α-galactosyl glycosphingolipids was accomplished. Commercially available 3,4,6-tri-O-acetylgalactal was used as the chiral starting material for both the sugar and phytosphingosine building blocks required for the synthesis of 1-O-(2-deoxy-α-d-galactopyranosyl)-2-docosanoylamino-1,3,4-octadecanetriol. The key step of the synthetic strategy was the stereoselective α-glycosidation of the azido precursor of sphingosine.