SYNTHESIS OF D-ribo- AND L-lyxo-PHYTOSPHINGOSINE: TRANSFORMATION INTO THE CORRESPONDING LACTOSYL-CERAMIDES

Article abstract of DOI:10.1016/0008-6215(88)85090-0

2,4-O-Benzylidene-D-threose (2) reacted with tetradecylmagnesium bromide to give the D-arabino- and the L-xylo-octadecanetetrol derivatives 3a and 3x as a readily separable mixture.Each of these compounds was transformed, via regioselective mesylation, azide displacement, benzylidene cleavage, and azide reduction, into D-ribo- (1r) and L-lyxo-phytosphingosine (1l), respectively. 3,4-O-Isopropylidenation of the intermediate azido derivatives 7r and 7l afforded the 1-O-glycosyl acceptors 2-azido-3,4-O-isopropylidene-D-ribo-1,3,4-octadecanetriol (8r) and 2-azido-3,4-O-isopropylidene-L-lyxo-1,3,4-octadecanetriol (8l), respectively.With the trichloroacetimidate-activated lactosyl donor 9, the expected glycosydes 2-azido-1-O-(2,3,6,2',3',4'6'-hepta-O-acetyl-β-lactosyl)-3,4-O-isopropylidene-D-ribo- and L-lyxo-1,3,4-octadecanetriol (10r and 10l) were obtained, which were conveniently transformed into the corresponding unprotected glycosphingolipids 14r and 14l.