New approaches to aromatic substitution reactions with carbon electrophiles

The thesis gives an account of work directed towards developing new reagent systems and methodology, with particular reference to the Friedel–Crafts and Vilsmeier–Haack reactions of aromatic and heteroaromatlc compounds. Ways of improving regioselectivity and developing a stereoselective Friedel–Crafts reaction have been investigated for a range of hetero-atom stabilised carbocations. This work is divided into two main areas: (1) the synthesis and use of pyrophosphoryl chloride in the Vilsmeier–Haack reaction, the results of this has shed new light on the mechanism of this classical reaction; (2) the control of the Friedel–Crafts reactions of bi-functional derivatives of glyoxylic acid and the use of chiral relays to induce diastereoselectivity. [Continues.]