Formal synthesis of ( − )-pereniporin B and ( − )-cinnamosmolide

The paper describes a new pathway for an efficient synthesis of natural and bioactive drimanic compounds ( − )-pereniporin B (1) and ( − )-cinnamosmolide (2) from ketodiol 7, an intermediate obtained before from accessible labdane diterpenoid (+)-larixol (3). The key step involves allylic bromination of acetate 8 with N-bromosuccinimide. The in vitro antimicrobial and antifungal activities of all compounds are also reported. Their structures were confirmed by both spectroscopic data and chemical transformations.