RESUMO
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.
RESUMO
The total synthesis of the recently reported marine natural product colombiasin A (1) and determination of its absolute configuration are reported. Two Diels-Alder cycloadditions and a palladium-catalyzed rearrangement are employed as key reactions to construct the tetracyclic framework of the target molecule. The enantioselective synthesis of colombiasin A utilizes Mikami's [(S)-BINOL-TiCl2] catalyst to asymmetrically introduce the first chiral center during the initial Diels-Alder reaction and, in conjunction with X-ray crystallographic analysis of a bromine containing derivative, led to the assignment of the absolute configuration of the natural product.