Kadcoccinones A–F, New Biogenetically Related Lanostane-Type Triterpenoids with Diverse Skeletons from <i>Kadsura coccinea</i>

Abstract

Six new lanostane-related triterpenoids, kadcoccinones A–F (<b>1</b>–<b>6</b>), were isolated from <i>Kadsura coccinea</i>. Compound <b>3</b> possesses a novel 6/6/9-fused carbocyclic core containing a rare oxabicyclo[4.3.1]­decane system. Compounds <b>4</b> and <b>5</b> are isomers representing the first example of the 18(13 → 12)-<i>abeo</i>-26-norlanostane triterpenoid. The absolute configurations of <b>1</b> and <b>4</b>–<b>6</b> were defined by X-ray diffraction and experimental ECD spectra, and that of <b>3</b> was elucidated by quantum chemical calculations. The plausible biogenetic pathway of <b>1</b>–<b>6</b> is postulated