Investigations of Diels-Alder reactions in ionic liquids

Room temperature ionic liquids comprise an unique class of solvent composed of organic and inorganic-based ions that are molten under ambient conditions. They are characterised by high solvent polarity and low vapour pressure, and can be tailored to have specific physical and chemical properties. Consequently, there has been great interest in exploiting these attributes to accelerate and control organic reactions. One such reaction, the Diels-Alder reaction, is an important [4+2] cycloaddition reaction used extensively in the preparation of cyclic and heterocyclic compounds. Understanding the factors involved in the enhancing this reaction in ionic liquids remains a subject of intense interest and the centrepiece of the dissertation. The objective of the research is to explore the Diels-Alder cycloaddition reaction in ionic liquids, with a view of developing high effective reactions systems, that operate under mild reaction conditions. The role that ionic liquid media plays in facilitating the Diels-Alder reaction is discussed. A range of physical and chemical modes of activating the reaction are discussed including pressure, the application of Lewis acid catalysts, microwave irradiation and ultrasound sonication and a comparison on the various modes of activation is provided. Importantly, the results of this study can lead to a better understanding of the ionic liquids as well as their utilization for other organic reactions.