This thesis describes research carried out on the synthesis of lithiation precursors used to investigate the ability of oxazoline activated benzene derivatives to undergo dearomatising cyclisations. Chapter 1 illustrates previous work in the area of dearomatising additions, including intra- and inter-molecular dearomatisations. An overview of relevant work conducted within the Clayden group is also described. Chapter 2 narrates the synthesis of lithiation precursors that contain a (4R,5R)-4,5-diphenyloxazoline activating group on the aromatic ring. The attempts to lithiate and dearomatise these compounds are shown. Chapter 3 describes the synthesis of achiral oxazoline activated O-allylic pre-lithiation substrates, and their ability to undergo dearomatising cyclisations. Also described is the attempts to find a suitable protecting group for N-allylic dearomatising cyclisations. Chapter 4 outlines the investigations carried out for the stereoselective synthesis of (4R,5R)-4,5-diphenyloxazolines, which have been used for the activation towards dearomatising cyclisation. Chapter 5 is an overview of the thesis and outlines possible future work.Chapter 6 contains the experimental methods and data pertaining to Chapters 2 to 5.