The work carried out during this PhD programme has been concerned with the reinvestigation and development of a general synthetic methodology towards the 3- acyltetramic acids (3-acylpyrrolidine-2,4-diones). Through a nitrile oxide cycloaddition strategy developed previously within our group we have synthesised a variety of 'masked' isoxazole precursors. We have further developed this strategy to include extension at the C-3 position in the bicyclic 3-methylpyrrolo[3,4-c]isoxazoles by deprotonation and condensation with a variety of aromatic aldehydes. Ring opening of the products with hydrogen yielded novel 3-(3-arylpropanoyl)tetramic acids, whilst using molybdenum hexacarbonyl produced 3-(3-arylpropenoyl)tetramic acids. Extension of the C-3 position on the 3-methylpyrrolo[3,4-c]isoxazoles has also been accomplished using aliphatic ketones.