Efficiently Building Hexacyclic Alkaloids

  • ChemPubSoc Europe Logo
  • Author: Andrei Dragan
  • Published Date: 03 April 2018
  • Source / Publisher: Chemistry – An Asian Journal/Wiley-VCH
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
thumbnail image: Efficiently Building Hexacyclic Alkaloids

Franchetine (pictured), a unique 7,17-seco-type norditerpenoid alkaloid, shows a highly congested hexacyclic architecture containing a characteristic N,O-acetal moiety which distinguishes it from norditerpenoid alkaloids. Some derivatives of this compound have shown promising analgesic (pain-relieving) activity with little toxicity, indicating it may be used as a lead molecule to develop new analgesic agents.


Jian‐Li Wang,  Liang Xu, and colleagues, Sichuan University, China, have developed an efficient synthesis of the hexacyclic framework of franchetine with the purpose of finding a new synthetic route to the natural molecule. The team started from a known tricyclic compound bearing a bicyclo[2.2.2]octane subunit. The six-membered A ring was formed through a radical cyclization of a iodoalkyne. The resulting exomethylene group was used to construct the C4 quaternary carbon of the target molecule. A reductive amination of the aldehyde installed the nitrogen atom, forming the N,O-acetal. Finally, the complete hexacycle of franchetine was formed by converting the bicyclo[2.2.2]octane moiety into a bicyclo[3.2.1]octane unit via a biomimetic Wagner–Meerwein rearrangement.


The synthesis involves 20 steps overall. According to the researchers, this method of constructing hexacyclic compounds could be an important methodological foundation for the synthesis of natural franchetine and related norditerpene alkaloids, such as aconitine.


 

Article Views: 657

Sign in Area

Please sign in below

Additional Sign In options

Please note that to comment on an article you must be registered and logged in.
Registration is for free, you may already be registered to receive, e.g., the newsletter. When you register on this website, please ensure you view our terms and conditions. All comments are subject to moderation.

Article Comments - To add a comment please sign in

Bookmark and Share

If you would like to reuse any content, in print or online, from ChemistryViews.org, please contact us first for permission. more


CONNECT:

ChemistryViews.org on Facebook

ChemistryViews.org on Twitter ChemistryViews.org on YouTube ChemistryViews.org on LinkedIn Sign up for our free newsletter


A product of ChemPubSoc Europe (16 European Chemical Societies)and Wiley-VCH