Synthesis of a typical N-acetylglucosamine-containing saponin, oleanolic acid 3-yl alpha-L-arabinopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranoside.

Oleanolic acid 3-yl alpha-L-arabinopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranoside, a cytotoxic saponin isolated from Acacia tenuifolia and Albizia subdimidiata with a typical structure of the N-acetylglucosamine-containing plant saponins, was synthesized. The synthesis adopted a stepwise glycosylation fashion employing glycosyl trifluoroacetimidates 5 and 9 and thioglycoside 12 as donors.