Two Enantiomeric Pairs of Meroterpenoids from Rhododendron capitatum

Two enantiomeric pairs of meroterpenoids, (−)- and (+)-rhodonoids A (<b>1a</b> and <b>1b</b>) and B (<b>2a</b> and <b>2b</b>), were isolated unprecedentedly from partially racemic mixtures that naturally occurred in Rhododendron capitatum. Their structures were fully determined by spectroscopic data, X-ray crystallography, and electronic circular dichroism analysis. Compounds <b>1a</b> and <b>1b</b> are the first examples of meromonoterpenes featuring a unique 6/6/6/4 ring system. Compounds <b>2a</b> and <b>2b</b> showed PTP1B inhibitory activity