Anwendung der α-Alkinon-Cyclisierung: Totalsynthese von (±)-Alben

Application of the α-Alkynone Cyclization: Total Synthesis of (±)-Albene A synthesis of the racemic form of the natural tricyclic hydrocarbon albene (1) from the Diels-Alder adduct 2 of tiglyl chloride and cyclopentadiene is described (24% yield). The key step 5→6 involves a thermal α-alkynone cyclization (Scheme 3), which is able to establish a new quarternary C-atom at an unactivated position with a high degree of regiospecificity.