Synthetic Studies Toward Gangliosides and Their Analogs: Synthesis of Appropriately Protected Core Oligosaccharides as Construction Blocks

Abstract
2-(Trimethylsilyl)ethyl 2, 3, 6, 2′-tetra-O-acetyl-3′-O-benzyl-6′-O-benzyloxymethyl-β-d-lactoside (9) was synthesized starting from acetobromolactose (1) via 2-(trimethylsilyl)ethyl β-d-lactoside (3). Compound 9 was converted to the trisaccharide derivative 17 after coupling with 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-α-d-galacto-pyranosyl bromide (11). Coupling of 17 with acetobromogalactose (19) gave the tetrasaccharide 20.