Total synthese of (±)-cyclolaurene, (±)-epicylolaurene and (±)-?-cuparenones

The first total synthesis of (±)-cyclolaurene (Image ) and (±)-epicyclolaurene (Image ), and a new route to (±)-?-cuparenone (Image ) are reported. Thus, orthoester Claisen rearrangement of the cinnamyl alcohol Image furnished the eneester Image . Anhydrous CuSO, catalysed intramolecular cyclopropanation of the diazoketone derived from the ene-acid Image , generated a diastereoisomeric mixture of cyclopropyl ketone Image . The Huang-Minlon reduction of the ketones Image and Image furnished the cyclolaurene (Image ) and epicyclolaurene (Image ), whereas regiospecific ring cleavage using lithium in liquid ammonia furnished the ?-cuparenone (Image ).