Total Synthesis of Lundurines and Related Alkaloids

Lundurines A-D were isolated in 1995 from the Malayan plant Kopsia tenuis, which has been used in folk medicine and is a rich source of biologically active alkaloids. Their intriguing hexacyclic framework includes an unprecedented cyclopropa [b] indole that has only ever been identified in lundurines. While these structural features have been attractive as synthetic targets, the first total synthesis was not reported until 2014. While lundurine B and D exhibit appreciable toxicity toward B16 melanoma cells and also reverse multidrug resistance in vincristine-resistant KB cells, their limited availability has prevented further studies for drug development. Therefore, the synthetic studies for these alkaloids and clarify the mechanism of their biological activity should contribute to medicinal chemistry. This review summarizes recent synthetic efforts in the total synthesis of lundurines and related alkaloids.