A Flexible Route to Indole Scaffolds – Formal Synthesis of (±)‐Mersicarpine

Abstract

The formal synthesis of racemic mersicarpine was accomplished in an operationally simple, reliable, and efficient manner in eight isolated steps. The use of a common intermediate increases the degree of synthetic flexibility and allows the construction of two completely different polycyclic alkaloid skeletons.

Total Synthesis of Leuconoxine, Melodinine E, and Mersicarpine through a Radical Translocation–Cyclization Cascade

“…Sequential cyclization steps form the remaining rings to give the natural product architectures. This general strategy has been used by several groups for leuconoxine/melodinine E syntheses, mersicarpine synthesis, as well as in divergent syntheses of multiple Aspidosperma targets –…”

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

“…In 2015, Gaich and co‐workers accomplished a protecting‐group‐free total synthesis of (−)‐leuconoxine ( 1 ) in 12 steps (0.5 % overall yield) by a novel photoinduced domino Witkop macrocyclization/transannular cyclization (Scheme ). This single transformation constructs three of the four rings of the diaza[5.5.6.6.…”

“…Due to their high complexity, many of these alkaloids became challenging targets for testing new synthetic strategies and methodology. Among them, the leuconoxine group of Aspidosperma alkaloids has garnered tremendous interest from the global synthetic community, which is reflected by six total syntheses in the last two years by the groups of Zhu, Tokuyama, Dai, Higuchi and Kawasaki, Gaich, and Stoltz and Liang . Leuconoxine ( 1 ), first isolated by Abe and Yamauchi in 1994 from Leuconotis eugenifolius , consists of a pentacyclic structure with three contiguous stereogenic centers including one that is quaternary and a labile aminal function (Figure ).…”

Inverse γ‐Turn‐Inspired Peptide: Synthesis and Analysis of Segetalin A Indole Hemi­aminal

“…Indole derivatives have received much attention in medical chemistry and natural products synthesis. [1][2][3] A host of natural products contain the indole core in the form of alkaloids and tryptophan derivatives, which creates new challenges for synthetic chemistry and offers new features and surprising reactivity. [4] Indole hemiaminals, which have already proved their antitumor properties in the inhibition of tubuline polymerization, are also interesting as structural motifs.…”