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.