The development of methods to construct new chemical bonds efficiently and selectively whilst minimising energy usage and waste production is of high importance in organic chemistry. Many current methods employ inefficient, costly and often toxic multi step protocols to generate new chemical bonds. The hydroacylation reaction is one method of reducing such inefficiencies. The development of an aerobic hydroacylation protocol in the Caddick group has recently allowed the functionalisation of aldehydes with a wide array of electron deficient alkenes. This process relies on trapping an acyl radical intermediate, from the auto-oxidation of aldehydes to acids, with a suitable alkene. Since aldehyde auto-oxidation takes place readily in the presence of atmospheric oxygen, the aerobic hydroacylation reaction can be conducted in aqueous media in the absence of any additional reagents. Following on from previous work in the group, this thesis describes studies towards expanding the scope of this novel methodology in the formation of C-N bonds. It also assesses the scalability of this reaction in order to make acyl hydrazides for further chemical transformations; as such, the development of protocols for the conversion of acyl hydrazides to carboxylic acid derivatives and to ketones will also be described. Chapter 1 provides an introduction to and a general overview of current methods of hydroacylation and acid derivative syntheses. Chapter 2 describes the development of conditions for, and application of aerobic hydroacylation towards C N bond formation, and the scalability of the hydroacylation reaction. Chapter 3 will focus on solving the failures of previous attempts for the conversion of acyl hydrazides to tertiary amides. Chapter 4 will demonstrate the applicability of acyl hydrazides to the synthesis of carboxylic esters and describe some of its limitations. Finally, chapter 5 will reveal acyl hydrazides as a new class of precursors for the chemoselective synthesis of ketones.
|Akhbar, A. R.
|University College London (University of London)
|Electronic Thesis or Dissertation
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