Total Syntheses of Tomentosones A and B

  • Author: ChemistryViews.org
  • Published: 15 October 2020
  • Copyright: Wiley-VCH GmbH
  • Source / Publisher: Organic Letters/ACS Publications
  • Associated Societies: American Chemical Society (ACS), USA
thumbnail image: Total Syntheses of Tomentosones A and B

Polycyclic polymethylated phloroglucinols (PPPs) are plant metabolites most often found in plants of the myrtle family or Guttiferae plants. PPPs have interesting, complex structures and can have useful biological activities, e.g., antibacterial, anti-inflammatory, or antiplasmodial effects. Antiplasmodial compounds fight parasites like those that cause malaria.


Tomentosones A and B (pictured), for example, are PPPs that were isolated from the rose myrtle shrub. These compounds have a 6/6/6/5/5/6 fused-ring system and differ only in the orientation of one isobutyl side chain. Tomentosone A has good antimalarial activity, while tomentosone B is significantly less active.


Yingjie Hu, Guangzhou University of Chinese Medicine, China, Hongxin Liu, Guangdong Provincial Key Laboratory of Applied Botany, Chinese Academy of Sciences, and Guangdong Academy of Sciences, China, Haibo Tan, Guangdong Provincial Key Laboratory of Applied Botany and Central South University, Changsha, China, and colleagues have performed the first biomimetic total syntheses of tomentosones A and B. The team based their syntheses on a possible biosynthetic pathway for tomentosones A and B.


The researchers first prepared an α,β-unsaturated ketone intermediate and reacted it with phloroglucinol (a benzenetriol) via a Michael addition. This was followed by an intramolecular dehydration and a Friedel–Crafts acylation to give rhodomyrtone, which contains the targeted 6/6/6 ring system. Rhodomyrtone was then subjected to a dehydroxylation/Michael addition/Kornblum–DeLaMare peroxide rearrangement cascade reaction with a peroxide intermediate to introduce the remaining rings and give tomentosones A and B. According to the researchers, this work could be useful for biosynthesis investigations, structure–activity relationship studies, and drug development involving these natural products.


 

 

Article Views: 712

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

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

Follow on Facebook Follow on Twitter Follow on LinkedIn Follow on Instagram RSS Sign up for newsletters

Magazine of Chemistry Europe (16 European Chemical Societies) published by Wiley-VCH