Involudispirones A and B: Sesterterpenes Containing a Dispiro Ring from <i>Stahlianthus involucratus</i>

Abstract

Abstract Involudispirones A ( 1 ) and B ( 2 ), a pair of cytotoxic sesterterpene stereoisomers containing a 1,2‐dioxadispiro[5.2.5.2]hexadecane ring, were isolated from the rhizomes of Stahlianthus involucratus . Their structures and absolute configurations were established on the basis of spectroscopic data and chemical conversion. Both 1 and 2 are cytotoxic.