Experimental Methods in the Chemistry of Iridolactones

This experimental work is concerned with developing different strategies for the preparation of a model iridolactones-ring systems Chapter 1 deals with the description of brasoside and its related iridolactones. An overview of previous synthetic approaches to brasoside is provided. The major synthetic efforts for the construction of both the AC-ring systems and the iridolactones-ring systems are reviewed. In chapter 2, a synthetic approach based on the ene reaction has been examined to prepare the AB-ring systems (8-memebered cis-fused bicyclic lactones) as well as their elaboration to the tricyclic ring (iridolactone) in the natural product. Chapter 3 reports a synthetic route to the preparation of densely functionalized AB-ring systems based on a cyclcoaddition involving cyclopentadiene with different ketenes followed by a ring expansion using Baeyer-Villager oxidation. An attempt to functionalize the resultant lactones derived from these protocols is described. Chapter 4 describes a stereoselective synthesis of the AB-ring system using a malonate-based approach.