Synthetic Investigation toward Acyl Group‐Free Escin Derivatives

Comprehensive Summary With protoescigenin as starting material and through orchestrated application of Yu and Schmidt glycosylation protocols, the synthesis of acyl group‐free escin derivatives was achieved for the first time. As the undesired non‐specific toxicity, originating from the existence of acyl groups on aglycone, prohibits the wide application of escins, the established strategies toward non‐acylated protoescigenin‐type saponins would dramatically ease the access to escin derivatives dispense of acyl groups, thereby speeding up the pace of pharmaceutical use of these valuable compounds. Chemical synthetic approach toward acyl group‐free escin derivatives has been successfully established, which would speed up the process of pharmaceutical applications of these valuable natural D/E‐ring simultaneously functionalized oleanane‐type saponins.