Structure and Absolute Configuration of Methyl (3<i>R</i>)‑Malonyl-(13<i>S</i>)‑hydroxycheilanth-17-en-19-oate, a Sesterterpene Derivative from the Roots of <i>Aletris farinosa</i>

Abstract

We report the isolation and structure elucidation of a new cheilanthane sesterterpene from the roots of <i>Aletris farinosa</i> that possesses an unusual malonate half-ester functional group. The structure of <b>1</b> was determined via mass spectrometry and 1D and 2D NMR spectroscopy, while its absolute configuration was determined via X-ray crystallographic analysis performed on its methyl ester derivative <b>2</b>