Related Experiment Video
Updated: Mar 28, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Synthesis of the aglycon of aspafiliosides E and F based on cascade reactions
Jing-Jing Wu1, Yong Shi1, Wei-Sheng Tian1
1The Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China. shiong81@sioc.ac.cn wstian@sioc.ac.cn.
Abstract:
A synthesis of C17α-OH-tigogenin, the aglycon of aspafiliosides E and F, is described. The main features of the synthesis are three cascade processes, which involve the iodo-lactonization of furostan-26-acid to open ring E, a cascade hydrolysis/intramolecular SN2 process to close ring E, and a cascade intramolecular redox-ketalization process to close ring F. This synthesis would enrich the strategies used for the manipulation of spiroketals in steroidal sapogenins and other substrates.

