Total synthesis of the bicyclo[6.3.0]undecane-based sesquiterpene (±)-asterisca-3(15),6-diene. Revision of the relative stereochemistry of the natural product

The first total synthesis of the novel bicyclic sesquiterpene hydrocarbon asterisca-3(15),6-diene is reported. As a consequence, the natural product is shown to possess structure 4 with a trans-5,8 ring fusion and not the previously assigned cis-asterisca-3(15),6-diene 3.