| Chapter 1. The identification and development of novel reactivity of propargylic esters containing a pendant epoxide are described. This method allows for the synthesis of highly functionalized cyclopentenone products. A range of different functional groups are tolerated in this transformation. Isolation of intermediates and their ability to be carried on to products provides mechanistic evidence for a 4pi-conrotatory ring closure to construct a carbon-carbon bond and stereospecifically set vicinal stereocenters.Chapter 2. An overview of multiple drug resistance (MDR) and the possibility for the use of chemical tools to elucidate this phenomenon is outlined. The Kopsia alkaloids are introduced and previous synthetic work is described. Two different initial synthetic plans were investigated. To close the key eight-membered ring of these natural products the first route makes use of a Friedel-Crafts acylation. The second route utilizes a Dieckmann cyclization to close this ring.Chapter 3. A route to lapidilectine B based on an Ugi four-component coupling is described. The Ugi reaction incorporates all the carbon atoms for lapidilectine B in a simple, high-yielding step. Elaboration of the Ugi-product is discussed and optimized, with special attention paid to the oxidative carbon-carbon bond cleavage necessary for the success of this strategy. A Friedel-Crafts hydroxyalkylation was utilized to form the eight-membered ring. Various methods for the formation of the final carbon-carbon bond of lapidilectine B are discussed. |
