Related Experiment Video
Updated: Jan 6, 2026

Preparation of Enantiopure Non-Activated Aziridines and Synthesis of Biemamide B, D, and epiallo-Isomuscarine
Published on: June 13, 2022
One-Step Biomimetic Synthesis of the Alkaloids Karachine, Valachine, and Sinometumine E
Alexander A Fadeev1, Amálie Vanoušková1, Martin Kotora1
1Department of Organic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 00 Praha 2, Czech Republic.
Abstract:
An efficient one-step synthesis of the protoberberine alkaloids karachine, valachine, and sinometumine E is described. This transformation relies on the biosynthetic hypothesis featuring vinylogous aldol, Michael, and Mannich addition reactions working in tandem under mild non-enzymatic conditions. The method employs renewable substrates in an atom-economical and operationally simple manner, allowing for a multigram-scale synthesis. The structure of karachine was confirmed crystallographically and showed the intramolecular n→π* interaction that enabled stereoselective nucleophilic addition to the carbonyl group.
More Related Videos
Related Concept Videos
Preparation of 1° Amines: Gabriel Synthesis
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
Synthesis of α-Substituted Carbonyl Compounds: The Stork Enamine Reaction
Aldehydes and Ketones with Amines: Enamine Formation Mechanism
Aldehydes and Ketones with HCN: Cyanohydrin Formation Overview
Aldehydes and Ketones with Amines: Imine and Enamine Formation Overview
Aldehydes and Ketones with Amines: Imine Formation Mechanism
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...

