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Synfacts 2025; 21(07): 664
DOI: 10.1055/a-2601-5058
Synthesis of Natural Products

Total Synthesis of (±)-Melohemsine K

Contributor(s):
Erick M. Carreira 
,
Nobel Saab
Lin S, Jing H, Duan J, Fang J, Zhao G, Xie X, Li H *, She X *. Lanzhou University, P. R. China
Total Synthesis of the Melodinus Alkaloid (±)-Melohemsine K.

J. Org. Chem. 2025;
90: 6339-6343
DOI: 10.1021/acs.joc.5c00545
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Keywords

(±)-melohemsine K - melodinus alkaloid - Pictet–Spengler reaction - 1,2-migratory rearrangement - retro-aza-Michael reaction - Diels–Alder reaction - intramolecular lactamization

Significance

Li, She and co-workers report the first total synthesis of the melodinus alkaloid (±)-melohemsine K. The synthetic strategy relies on a tandem enamine formation/retro-aza-Michael reaction/Diels–Alder reaction/intramolecular lactamization to build the tricyclic core.


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Comment

The indole-fused azepine E was prepared through a 1,2-migratory rearrangement of C and subsequent olefin reduction. Enamine formation with aldehyde F followed by a retro-aza-Michael reaction set the stage for an intramolecular Diels–Alder cycloaddition that gave access to I. Lactamization and demethylation completed the synthesis of (±)-melohemsine K.


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Publication History

Article published online:
23 June 2025

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