Syntheses of several oligosaccharides, required for immunol. studies, e.g., p-trifluoroacetamidophenyl O-a-D-glucopyranosyl-(1->4)-a-D-galactopyranoside and 8-methoxycarbonyloct-1-yl O-a-D-galactopyranosyl-(1->3)-O-b-D-galactopyranosyl-(1->4)-2-acetamido-2-deoxy-b-D-glucopyranoside, are reviewed with 96 refs. A synthesis of a sucrose deriv. suitable for selective acylation at OH-2, OH-3 and/or OH-4 is also described. Furthermore, reductive opening of acrolein acetals and benzylidene acetals is examd. The dependency of regioselectivity on solvent and reagents is investigated. [on SciFinder (R)]