Investigation on Coupling Reaction of Fragments Towards Total Synthesis of Pyrenophorin

Molecules belonging to the medium and large size rings lactones have attracted considerable attention from synthetic chemists due to their interesting biological properties. Due these structural features and importance, we have accepted the challenging to prepare Pyrenophorin 1 (Figure 1), a symmetric sixteen-membered diolide isolated from Pyrenophora avenae 1 which displays potent antifungal activity. In our synthetic strategy to obtain a half-part of this molecule, we found several problems to perform a coupling reaction of fragments 3 and 4. Several efforts were focused on coupling reaction to construct a fragment 2. This work shows our results in this direction.