Lactones, 2. Synthesis of Enantiomeric Pairs of Lactones with the Pinane or the Fenchane system

Starting from (+)‐ and (−)‐myrtenols, and via iodolactonization, the enantiomerically pure tricyclic lactones, with pinane systems, were obtained. In the course of an acidic lactonization of the γ,δ‐epoxy esters 6a and 6b, the rearrangement of the pinane system to that of the fenchane was observed. The absolute configurations of the newly formed chiral centres of the lactones 4b and 11b were established by X‐Ray diffraction analyses.