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<abstract xmlns="http://eprints.org/ep2/data/2.0">N-Methylwelwitindolinone C isothiocyanate (7), isolated from the blue green algae Hapalosiphon welwitschii and Westiella intricate, is a structurally novel alkaloid related to the welwitindolinone family. This thesis describes studies towards the total synthesis of this natural product. &#13;
Chapter One introduces the biological activities and the proposed biosyntheses of the welwitindolinone alkaloids. The synthetic studies towards the synthesis of this class of natural products will be also discussed. &#13;
Chapter Two describes the different strategies towards the synthesis of a bicyclo[4.3.1]decane scaffold possessing a gem-dimethyl group present in the natural product 7. The geminal group was envisioned via a methyl addition to a carbonyl, a deprotonation of a sulfone or an intramolecular Michael addition. Generation of the desired skeleton 182 was achieved by using an intramolecular palladium-catalysed α-arylation of a trimethylsilyl enol ether. &#13;
Chapter Three describes various attempts to the direct installation of a nitrogen functionality at the bridgehead position. In an indirect mode, a regioselective deprotonation allowed functionalisation of the desired bridgehead position and the access to isocyanate 297 and diketoazide 276, respectively obtained from a [3,3]-sigmatropic rearrangement and an aza- Michael reaction. A three step sequence involving a regioselective deprotonation of diketoazide 276, followed by aldol condensation and dehydration led to the advance intermediate 306. &#13;
Chapter Four describes the recent breakthrough in the synthesis of the welwitindolinone alkaloids. The total synthesis of N-methylwelwitindolinone D isonitrile (19) and N-methylwelwitindolinone C isothiocyanate (7), along with related studies reported this year. &#13;
Chapter Five includes the experimental procedures and analytical data for the preparation of novel compounds described during the course of this study. &#13;
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