On the structure of penipratynolene and WA

The antipode of the structure proposed for the natural product penipratynolene in the literature was synthesized in high enantiopurity via an chiron approach and fully characterized. However, substantial differences were observed between the physical and spectroscopic data of the synthetic sample and those reported for the natural penipratynolene. Possible causes for the discrepancies are proposed on the basis of acquisition and comparison of additional data. The present work also provides the only piece of synthetic evidence for an antifungal natural product WA, the corresponding acid of the antipode of natural penipratynolene.