The Diaza[5.5.6.6]fenestrane Skeleton—Synthesis of Leuconoxine Alkaloids

Among the Aspidosperma-derived monoterpene indole alkaloids, the leuconoxine subgroup has drawn significant attention from the synthetic community during the past few years. This Minireview summarizes the hitherto six completed total syntheses of leuconoxines emphasizing the different strategies for assembling the key structural motif, an unprecedented diaza[5.5.6.6]fenestrane skeleton. In addition, the proposed biogenetic relationships within the group of these alkaloids are described.