The synthesis of solasodine F-homo-analogues†
Solasodine derivatives continue to be attractive targets for synthetic chemists due to their interesting biological properties. Herein, we report a concise synthesis of solasodine analogues containing the seven-membered F ring from diosgenin. The key intermediate in the synthesis of 26a-homosolane derivatives was 26-cyanopseudodiosgenin. After reduction of the cyano group, the seven-membered ring was closed with MgBr2·Et2O to yield 26a-homosolanes as a mixture of 22R and 22S epimers. The acylation of the obtained mixture led to the diastereomerically pure 22S N-acylated 26a-homosolasodine derivatives. Moreover, we describe one-step protocol for stereoselective synthesis of 22R-cyanofurostane by treatment of diosgenin with TMSCN/BF3·Et2O.
- This article is part of the themed collection: Synthetic methodology in OBC