Two Enantiomeric Pairs of Meroterpenoids from <i>Rhododendron capitatum</i>

Abstract

Two enantiomeric pairs of meroterpenoids, (-)- and (+)-rhodonoids A (1a and 1b) and B (2a and 2b), 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 1a and 1b are the first examples of meromonoterpenes featuring a unique 6/6/6/4 ring system. Compounds 2a and 2b showed PTP1B inhibitory activity.