Easy Access to the Voaketone Ring System.

Abstract Intramolecular aldol condensation of ketoaldehyde 8 affords three new compounds: enone 9 , hydroxyketone 10 , and enone 11 . Enone 9 possesses the ring system of (−)-voaketone ( 1 ), which is a skeletal rearrangement product of the indole alkaloid (−)-voacangine.