Synthesis of l-arabinopyranose containing hederagenin saponins

The synthesis of eight hederagenin saponins, five of which are natural products, and their methyl esters is described as part of an ongoing study of the biological activity of triterpenoid saponins. Six disaccharides consisting of an l-arabinopyranose glycosylated in positions 2, 3, or 4 with a β-d-xylopyranose or a β-d-glucopyranose residue, respectively, were synthesized in good to excellent yields. The saponins were then prepared in good yields through glycosylation with a suitably protected hederagenin derivative followed by total deprotection and treatment with diazomethane.