The project was divided into three parts: 1. Synthesis of perfluoro (highly fluorinated chain) compounds. The aim was to prepare modified phosphorous and nitrogen containing organic molecules by attaching to them highly fluorinated tags. A review of the current literature in the area is given. The fluorous compounds at room temperature are typically immiscible with organic solvents and water. The method gives an advantage of simple liquid-liquid separation and in some cases an opportunity to recover partially the starting materials. 2. Synthesis of fluorine containing heterocyclic compounds. The incorporation of fluorine in heterocyclic compounds may have only a small effect on their conformation, but may have a large electronic effect. This may give rise to novel biological activity. A review of the current literature in the area is given. Using simple aldehydes as starting materials, in the presence of Lewis acids, a straightforward procedure has been developed to prepare fluorinated heterocycles. 3. Synthesis of heterocyclic natural products. Using a related method to the one previously developed in part 2, the same Lewis acid promoted reaction has been applied to the total synthesis of two physiologically active natural products. Finally, the experimental details for each of the above three sections will be given. The work described in this thesis is the author's own work, accept where appropriate reference is made. Work previously published by a colleague {Tetrahedron Lett.^ 2002, 43, 2807-2810^66a) has been repeated herein and the results optimised.