In conclusion, we have developed a unified approach
to the palmarumycin and preussomerin natural products
culminating in the synthesis of two achiral, one racemic,
and five enantiomerically pure members of the palmarumycin
family and establishing the absolute configuration
in three cases for the first time. In addition we have
achieved an enantioselective synthesis of (-)-preussomerin
G (11), this being the first enantioselective synthesis
of the preussomerin class of natural products. These
natural products were synthesized utilizing a chiral
phase transfer catalyzed epoxidation procedure and a
potentially biomimetic oxidative cyclization as the key
synthetic steps. We are currently applying the same
methodology to the synthesis of additional preussomerins
and diepoxins.