Analogs of sialyl-α(2→6)-lactotetraosylceramide and sialyl-α(2→6)-neolactotetraosylceramide, in which theN-acetylneuraminic acid residue is replaced by a 3-deoxy-d-glycero-d-glacto-2-nonulopyranosylonic acid (KDN) unit, have been synthesized. MethylO-(methyl 4,5,7,8,9-penta-O-acetyl-3-deoxy-d-glycero-α-d-galacto-2-nonulopyranosylonate)-(2→6)-2,4-di-O-benzoyl-3-O-benzyl-1-thio-β-d-galactopyranoside (6) was prepared from the phenyl β-thioglycoside derivative1of KDN and 2-(trimethylsilyl)ethyl 3-O-benzyl-β-d-galactopyranoside (2) in four steps. Each coupling of 2-(trimethylsilyl)ethylO-(2-acetamido-4,6-O-benzylidene-2-deoxy-β-d-glucopyranosyl)-(1→3′)-per-O-benzyl-β-lactoside (7) or 2-(trimethylsilyl)ethylO-(2-acetamido-3,6-di-O-benzyl-2-deoxy-β-d-glucopyranosyl)-(1→3′)-per-O-benzyl-β-d-lactoside (8), with6gave the pentasaccharides9and13in good yields. Compounds9and13were converted into the corresponding α-trichloroacetimidates12and16which on glycosylation with (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol (17), gave the β-glycosides18and21, respectively. Finally,18and21were transformed,viaselective reduction of the azido group, condensation with octadecanoic acid,O-deacylation, and saponification of the methyl ester group, into the target compounds20and23, respectively.