Stereochemistry of trevoagenin a and b and configuration at C24 of the 2or-ocotillones

Abstract

Of the triterpenes of the ocotillol type till now only the stereochemistry of the isomers of the 20S-series has been established. Our work reports the configuration at C24 of the isomers of the 20R-series as a consequence of the determination of the stereochemistry of trevoagenin A (2a) and B (la), recently isolated from Trevoa trinervis Miers.