Synthesis of Sphingosines, Part 8. Synthesis of Methyl-branched Sphingosines

✍ Scribed by Bär, Thomas ;Kratzer, Bernd ;Wild, Robert ;Sandhoff, Konrad ;Schmidt, Richard R.

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 829 KB
• Volume: 1993
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199319930168

✦ Synopsis

Abstract

Treatment of 2,4‐O‐benzylidene‐D‐threose (3) with the Wittig reagent obtained from 2‐bromopentadecane furnished 5‐methyloctadec‐4‐ene derivatives (E,Z)‐8. The introduction of the azido group into the 2‐position and acid‐catalyzed removal of the benzylidene protective group afforded 5‐methyl‐substituted azidosphingosines (E)‐10 and (Z)‐10 which were converted via azide reduction into the corresponding sphingosines (E)‐1 and (Z)‐1, respectively. Reaction of 3 with methylmagnesium bromide, ensuing selective 2‐O‐mesylation, and then 4‐O‐oxidation gave ketone 13. The Wittig reaction of 13 with triphenyltetradecylphosphorane afforded exclusively 4‐methyloctadec‐4‐ene derivative (Z)‐16 which was transformed into 4‐methyl‐substituted sphingosine (Z)‐2 as described above. For the synthesis of the corresponding E isomer, 3 was converted into carbinols 21h,l. 2‐O‐Silyl protection and then water elimination furnished 4‐methyl‐substituted (4__E__)‐octadec‐4‐ene derivative (E)‐23 which was transformed into (E)‐2.