Recent Progress Toward Total Syntheses of Iheyamines A and B

This perspective article describes the recent progress in the total syntheses of iheyamines A and B. Since iheyamine A possesses a highly unique unsymmetrical azepino-2,2’-bisindole scaffold, novel strategies to construct the basic scaffold have been developed, and unique total syntheses have been reported based on these strategies. In addition, because iheyamine B bears vicinal 2-oxopropyl moieties with a trans-configuration in the azepine scaffold of iheyamine A, the first asymmetric total synthesis of iheyamine B took a substantially longer time than iheyamine A to complete. Due to the unusual structure of iheyamine B and some discrepancies in the experimental data between the isolated and synthesized iheyamine B, some controversial issues regarding whether iheyamine B is a natural product or an artifact have been raised and will be discussed.