Five-membered ring annelation via thermal rearrangement of β-cyclopropyl-αβ-unsaturated ketones: a new total synthesis of (±)-zizaene

The bicyclic αβ-unsaturated ketone (2), conveniently prepared by thermal rearrangement of (1), is converted, via an 11-step sequence, into the tricyclic ketone (15), thus formally completing a new total synthesis of (±)-zizaene (3).