Total Synthesis of (+)-Talassimidine and (+)-Talassamine

Key words

hetidine alkaloids - (+)-talassimidine - (+)-talassamine - Stille coupling - dipolar cycloaddition - aldol addition

Significance

(+)-Talassimidine and (+)-talass­amine, two hetidine alkaloids, were first isolated by Nishanov et al. from the plant Aconitum talassicum. Zhang and co-workers report an asymmetric total synthesis of (+)-talassimidine and (+)-talassamine, overcoming the challenges imposed by the hexa­cyclic ring system and oxidation pattern of this family of natural products.

Comment

Stille coupling of enantioenriched aryl stannane A gives precursor C for the key dipolar cycloaddition, assembling the tetracyclic skeleton in F. Arene cyclopropanation yields G, which is elaborated to ketone I via cyclopropane opening. Aldol addition of aldehyde J then gives rise to mesylate K, which is transformed into two natural products, (+)-talassimidine and (+)-talassiminie.

Publication History

Article published online:
20 July 2021