Syntheses of Two Pairs of Enantiomeric C18-Sphingosines and a Palmitoyl Analogue of Gaucher Spleen Glucocerebroside

Sixteen kinds of chiral C4-epoxides [(-)-10a-d, (+)-10a-d, (-)-11a-d, (+)-11a-d], which are synthons in our synthetic strategy for complex lipids, have been prepared from (2Z)-2-butene-1, 4-diol (6) by employing a Sharpless asymmetric epoxidation. By using the chiral C4-epoxides [(+)-10a, (-)-10a, (-)-11a, (+)-11a] as starting compounds, two pairs of enantiomeric (D-erythro, L-erythro, D-threo, and L-threo)-C18-sphingosines (1, 2, 3, 4) have been synthesized via a regioselective ring-opening of the epoxide ring with azide anion followed by reduction of the azide group to an amino group and a Wittig reaction. Furthermore, D-erythro-C18-sphingosine (1) has been converted to a palmitoyl analogue (5a) of Gaucher spleen glucocerebroside (5) through a reaction pathway including successive condensations with palmitic acid and D-glucose.