荒井 秀

Cyano (CN) groups are equivalent to carbonyl as well as amino- and hydroxymethyl groups. Therefore, their catalytic introduction under metal catalysis is an important issue in synthetic organic chemistry. Ni-catalyzed hydrocyanation is one of the most well-investigated, powerful tools for installing a CN group. However, it is still difficult to control chemo- and regioselectivity. In this review, the author uses allenes to enable regio-, stereo-, and face-selective transformations to natural product synthesis and axial chirality transfer.

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.