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Synthesis of Sphingosines, Part 8. Synthesis of Methyl‐branched Sphingosines
Author(s) -
Bär Thomas,
Kratzer Bernd,
Wild Robert,
Sandhoff Konrad,
Schmidt Richard R.
Publication year - 1993
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.199319930168
Subject(s) - chemistry , wittig reaction , azide , bromide , silylation , derivative (finance) , reagent , ketone , stereochemistry , medicinal chemistry , organic chemistry , catalysis , financial economics , economics
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 .