Synthesis of a new glycosphingolipid, neurosporaside, from Neurospora crassa.

The glycosphingolipid neurosporaside (α-D-Glcp-(1 → 2)-β-D-Galp-(1 → 6)-β-D-Galp-(1 → 6)-β-D-Galp-(1 →)-Cer) occurs in Neurospora crassa. We attempted to synthesize neurosporaside by block synthesis (route A) and linear synthesis (route B). Oligosaccharide derivatives were synthesized using trimethylsilyltrifluoromethanesulfonate and N-iodosuccinimide/trifluoromethane sulfonic acid as promoters. The target tetrasaccharide could not be attained via route A, but route B showed potential: glycosidic bonds (β-D-Galp-(1 → 6)-β-D-Galp-(1 → 6)-β-D-Galp) were formed stereoselectively, leading to the synthesis of glycosphingolipid 2.