Total Synthesis of Colombiasin A.

Colombian corals of the species Pseudopterogorgia elisabethae produce the title compound, colombiasin A (1). This structurally novel, biologically active tetracyclic compound has now been synthesized for the first time in racemic form. Preliminary studies toward the asymmetric total synthesis of both enantiomers indicate that the determination of the absolute stereochemistry can be expected soon.