| Streszczenie: | <p>This dissertation explores how the scope of hydrogen borrowing reactions can be further expanded to use both primary and secondary alcohols to form α-, β- and α,β-branched aryl ketones. <em>ortho</em> Substituents were critical in enabling the hydrogen borrowing alkylation by inducing a non-coplanar geometry of the aryl–ketone motif, which provides various beneficial effects that contribute to the success of the reaction.</p> <p>The versatility of the hydrogen borrowing reaction was further improved by introducing a vinylcyclopropane rearrangement into the reaction manifold prior to enone reduction. Control studies and modified substrate provide insight into the mechanism of the reaction.</p> <p>The synthetic utility of pentamethylphenyl (Ph*) ketones was enhanced through electrophilic cleavage to form various carboxylic acid derivatives. Phenol derivatives of Ph* ketones were also found to undergo a related oxidative cleavage of the derivatised Ph* group to form esters and carboxylic acids.</p> <p>Phenol and aniline derivatives of Ph* ketones formed tetrasubstituted α-keto centres in the hydrogen borrowing reaction, a remarkable result that could not have been possible using conventional aldol chemistry. Attempts were made to explore the formation of tetrasubstituted α-keto centres in the hydrogen borrowing reaction with other aryl ketone derivatives.</p> <p>Structural changes were observed by X-ray crystallography that were consistent with the alleviation of steric interactions between the aryl group and ketone substituent, providing evidence that <em>ortho</em>-substitution provides multiple benefits that drive the hydrogen borrowing reaction. Substituents at the <em>meta </em>and <em>para</em> positions of the aryl ring result in structural distortions that are directly responsible for the "buttressing" effect. IR, <sup>13</sup>C and <sup>15</sup>N NMR spectroscopy were also employed to study the effects of non-coplanar geometries of the amino, nitro and carbonyl groups.</p>
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