Syntheses of Annoglabasin A and Annomosin A, ent‐Kaurane Diterpenoids from Annonaceae, Using Stevia Sweetener as a Cost‐Effective Synthetic Source

A practical and cost‐effective method is developed for preparing steviol from commercially available stevia sweetener. As steviol can be efficiently converted into ent ‐kaurenol, this strategy enables the large‐scale synthesis of ent ‐kaurenol and its derivatives. To demonstrate the versatility of ent ‐kaurenol as a synthetic intermediate, several derivatives are synthesized, including carboxylic acid and diol compounds with controlled C‐16 stereochemistry. This methodology is applied to the synthesis of the ent ‐kaurane dimer annomosin A, isolated from Annona squamosa , and the bioactive diterpene annoglabasin A, from Annona glabra . The approach allows access to structurally diverse kaurane derivatives with defined C‐16 stereochemistry and is readily extendable to the synthesis of kaurane dimers. Given the limited understanding of the biosynthetic pathways and biological functions of natural kaurane dimers, this synthetic strategy provides a valuable platform for future structural and functional investigations.