Total Synthesis of Paralemnolide A.

The first total synthesis of tricyclic bisnorsesquiterpene paralemnolide A, isolated from the soft coral Paralemnalia thyrsoides, was achieved. This synthesis features the lactonization of the cyclohexene derivative having a tert-butyl ester via stereoselective epoxidation followed by treatment with a Brønsted acid and construction of the novel tricyclic skeleton by an intramolecular Reformatsky-Honda reaction.