Transition-Metal-Free Hydroxylation of Aryl Halides and Nitroarenes

This thesis describes the development of two new methods for the synthesis of phenols. Chapter 1 provides an introduction into this area and sets out the aims of this project. Chapter 2 describes a single-step reaction protocol for synthesising phenols from aryl halides using an oxime anion as a hydroxide surrogate. The synthesis of the oxime reagent could be achieved simply by condensing an aryl aldehyde with hydroxylamine. The reaction protocol could be applied to complex molecular structures alongside simple aryl halides. Many functional groups could be tolerated, however substrates generally required electron-withdrawing group substituents for a successful reaction. Some substituents did not promote the reaction if they were in the meta- or ortho- positions. Mechanistic studies suggested that a radical-nucleophilic substitution (SRN1) mechanism was operative. Chapter 3 describes a protocol for the conversion of nitroarenes into phenols using the same oxime reagent. This reaction showed similar trends in reactivity in regard to substituent effects. However, higher reaction temperatures were generally employed to promote this reaction