Mollebenzylanols A and B, Highly Modified and Functionalized Diterpenoids with a 9‑Benzyl-8,10-dioxatricyclo[<sup>1,5</sup>]decane Core from <i>Rhododendron molle</i>

Two highly modified and functionalized diterpenoids, mollebenzylanols A (<b>1</b>) and B (<b>2</b>), and a known grayanane diterpenoid rhodojaponin III (<b>3</b>) were isolated from <i>Rhododendron molle</i>. Their structures were determined by spectroscopic data analysis, an electronic circular dichroism (ECD) exciton chirality method, ECD calculations, and X-ray diffraction analysis of the <i>p</i>-bromobenzoate ester of <b>1</b> (<b>1a</b>). Compounds <b>1</b> and <b>2</b> possess an unprecedented diterpene carbon skeleton featuring a unique 9-benzyl-8,10-dioxatricyclo­[<sup>1,5</sup>]­decane core, and their plausible biosynthetic pathways are proposed. Their PTP1B inhibitory activity and modes of action were investigated.