On the Stereochemistry of Natural Irones, Dihydroirones, and their Precursors

Abstract Natural irones from the essential oil of Iris rhizomes develop by oxidative degradation of C 31 ‐triterpenoids produced by the plant. Two enantiomeric forms of irones are found in Iris , oils of different origin. The optical properties and CD spectra of irones, dihydroirones and their C 31 ‐precursors are reported and their absolute stereochemistry is determined.