Find in Library

Saikosaponin A (SSa) and D (SSd) are typical oleanane-type saponins featuring a unique 13,28-epoxy-ether moiety at D ring of the aglycones, which exhibit a wide range of biological and pharmacological activities. Herein, we report the first synthesis of saikosaponin A/D (<b>1</b>–<b>2</b>) and their natural congeners, including prosaikosaponin F (<b>3</b>), G (<b>4</b>), saikosaponin Y (<b>5</b>), prosaikogenin (<b>6</b>), and clinoposaponin I (<b>7</b>). The present synthesis features ready preparation of the aglycones of high oxidation state from oleanolic acid, regioselective glycosylation to construct the β-(1→3)-linked disaccharide fragment, and efficient gold(I)-catalyzed glycosylation to install the glycans on to the aglycones.