Substitution Reactions in Aromatic Systems

Abstract

Quantitative aspects of recent developments in theories of electrophilic aromatic substitution are reviewed, and it is shown how better understanding of these theories can help to predict with greater accuracy, optimum conditions for maximum yield of a required product in a given substitution.
Particular reference is made to the acid-catalysed hydrogenexchange reaction as a tool for diagnosing new electronic effects, and to its usefulness in predicting isomer product ratios in other substitutions. In relation to this, new quantitative work on the electrophilic substitution of some derivatives of naphthalene is described in some detail.
Some recently elucidated factors which affect the ortho: pararatios are described and the need to consider strain as a factor in controlling isomer ratios in substitution of aromatics possessing cyclic side-chains is emphasized.