Double stereodifferentiation in asymmetric dihydroxylation: application to the first diastereoselective synthesis of -xylo-[2R,3S,4S]-C18-phytosphingosine

The first diastereoselective synthesis of xylo-(2R,3S,4S)-C₁₈-phytosphingosine (1) has been achieved by double stereodifferentiation of enantiomerically enriched terminal olefin 14 using (DHQD)₂–PHAL ligand in an asymmetric dihydroxylation with a diastereomeric ratio of 83:17. This phytosphingosine was fully characterized by the physical and spectral data of the corresponding tetraacetate 21.