Chloranthones A-D: Minor and Unprecedented Dinor-Eudesmenes from Chloranthus elatior

Four novel naturally occurring diastereoisomers of dinor-eudesmenes, named chloranthones A-D (1-4, resp.), were isolated as minor components from the EtOH extract of the aerial parts of Chloranthus elatior. The unprecedented framework was established using extensive 2D-NMR techniques. Their absolute configurations were deduced from the observed Cotton effects in their circular dichroism (CD) spectra. A plausible biosynthetic pathway to the dinor-eudesmenes is proposed.