Biologically active glycosides from asteroidea, XXIV. Stereochemistry of the four diastereomers of phytosphingosine

Diastereomeric D‐ribo‐(2S,3S,4R)‐, D‐lyxo‐(2S,3S,4S)‐, D‐arabino‐(2S,3R,4S)‐, and D‐xylo‐(2S,3R,4R)‐C16‐phytosphingosine tetraacetates 2–5 were synthesized from the oxazoline 11 derived from (S)‐serine. Detailed physical data were obtained and the stereochemistry can be readily identified, regardless of any new phytosphingosine moiety of the glucosphingolipids which may be detected in nature.