Determination of the absolute configuration at the two cyclopropane moieties of plakoside A, an immunosuppressive marine galactosphingolipid

The absolute configuration of plakoside A {(2S,3R,11R*,12S*)-2-[(2′′′R,5′′′Z,11′′′R*,12′′′S*)-2′′′-hydroxy-11′′′,12′′′-methylene-5′′′-docosenamido]-1-O-[2′-O-(3′′-methyl-2′′-butenyl)-β-d-galactopyranosyl]-11,12-methylene-1,3-docosanediol} was determined as 11S,12R,11′′′S,12′′′R by its degradation to two cyclopropane-containing fatty acids followed by their derivatization with a chiral reagent and subsequent HPLC analysis of the resulting derivatives.