ConspectusIndole alkaloids, one of the largest classes of alkaloids, serve as an important and rich source of pharmaceuticals and have inspired synthetic chemists to develop novel chemical transformations and synthetic strategies. Many biologically active natural products contain challenging indoline scaffolds, which feature a C3 all-carbon quaternary stereocenter that is often surrounded by a complicated polycyclic ring system. The creation of this quaternary stereocenter creates an inherent synthetic challenge because the substituents on the carbon center cause high steric repulsion. In addition, the presence of nitrogen atoms within the surrounding polycyclic rings can lead to synthetic difficulties.Oxidative coupling between two sp3-hybridized carbon anions provides a unique and powerful method for building C–C single bonds, especially for generating a C–C bond that joins one or two vicinal quaternary stereocenters. Although chemists have known of this transformation for a long time, they have only ap...

Kopreasin A, a New Indole Alkaloid from Kopsia arborea.

Intramolecular dearomative oxidative coupling of indoles: a unified strategy for the total synthesis of indoline alkaloids.

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A new alkaloid, kopreasin A (1) was isolated from the leaves of Kopsia arborea (Apocynaceae) together with ten known indole alkaloids (2 - 11), and the structure was elucidated by NMR spectral analysis using 2D techniques. These indole alkaloids showed a moderate vasorelaxant activity on isolated rat aorta ring.

Kopreasin A, a New Indole Alkaloid from Kopsia arborea.

Citations

Intramolecular dearomative oxidative coupling of indoles: a unified strategy for the total synthesis of indoline alkaloids.

References

Kopreasin a, a new indole alkaloid from kopsia arborea

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