Azidosphingosine Glycosylation in Glycosphingolipid Synthesis

The 3-O-protected azide derivatives of C 18 -sphingcsine s me 1A - 1C reacted with O -acyl protected trichloroacetimidates of D-glucose, D-galactose, and laczose to afford the corresresponding β-glycosides in high yields. Ortho-ester formation in the case of O -acetyl compound could he avoided by increasing the amount of bcrcn trifluoride diethyl ether catalyst. Deprotection. and azido group reduction provided the psychosines of D-gluccse, D-galactose, and lactose ( 5 , 10 , and 15 ), which are versatile intermediates for the attachment of different fatty acii residues. With hexadecanoyl chloride, for instance, the corresponding glycosphingolipids 6 , 11 , and 16 , respectively, were obtained.