Prins-Pinacol synthesis of bicyclo[331]nonanones and application towards the total synthesis of papuaforin A

The present thesis concentrates on the development of the Prins-Pinacol mediated synthesis of bicyclo[3.3.1]nonanones and its application towards the total synthesis of papuaforin A. In addition, an exploratory study of the oxy-Cope/Claisen/ene cascade reaction and the total synthesis of (+)-isofregenedol are presented. These subjects are divided into four chapters. The first part of this thesis describes the discovery and examination of a novel microwave-induced rearrangement of propargyl vinyl ethers delivering cis-bicyclic unsaturated lactones. The methodological investigation of the Prins-Pinacol rearrangement oriented towards the construction of bicyclo[3.3.1]nonanones is discussed in Chapter 3. The synthesis of various precursors and the optimization of the key step are presented. The reactivity observed for the isopropylidene and benzylidene oxocarbenium precursors is then compared. The effect of the substitution of the alkene moiety and at the ring junction is also examined. The Prins-Pinacol rearrangement of complex Diels-Alder cycloadducts is described last. The fourth chapter depicts the advancement towards the total synthesis papuaforin A. The synthesis of a model compound possessing the bicyclo[3.3.1]nonanone core of the natural product is first presented. The progress towards the actual total synthesis is discussed next. Finally, the application of the gold(I)-catalyzed benzannulation of hydroxyenynes to the de novo synthesis of (+)-isofregenedol is described in Chapter 5