Asymmetric α-oxygenation of carbonyl compounds

Knowles, Deborah Ann 2009. Asymmetric α-oxygenation of carbonyl compounds. PhD Thesis, Cardiff University.

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Abstract

The a-hydroxy carbonyl group represents a significant building block in organic synthesis, which is reflected by the extensive synthetic efforts directed towards introduction of this group in a chemo- regio-, stereo-, and enantioselective manner. Traditional methods for the a-oxygenation of carbonyl compounds involve the formation and reaction of air-sensitive intermediates. This thesis describes an alternative metal-free approach to the formation of C-O bonds a- to a carbonyl group, in an asymmetric manner. Chapter l provides an overview of the literature methods for the a-oxygenation of carbonyl compounds, incorporating recent advances in this field achieved previously within the group, following discovery of 63*HC1 to affect a one-pot a-oxygenation transformation. Chapter 2 outlines our objectives and describes methods for the preparation of chiral hydroxylamine reagents based on the generic structure 108. The focus of this chapter is on establishing asymmetric transformations and their optimisation. Chapter 3 examines varying the size and nature of the 0-acyl group (R2) in order to determine its effect on the asymmetric reaction. Chapter 4 studies the influence of relative electronic effects on the asymmetric reaction, by varying the electronic properties of R1 and R2. Chapter 5 explores the role of the TV-substituent (R1) on an asymmetric a-oxyacylation transformation. Application of our methodology to other carbonyl substrates is also examined. Chapter 6 investigates an alternative method for the synthesis of chiral a-oxygenated carbonyl compounds, involving formation and reaction of chiral nitrones. In recent years methods have been developed within the group for the a-oxycarbonoylation, oxycarbamoylation and oxytosylation of carbonyl compounds. Chapter 7 investigates application of the methodology developed within this thesis to each of these transformations. Following an interesting observation, a novel procedure for the conversion of primary amines into ketones was developed, which is discussed in Chapter 8.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Chemistry
Subjects:	Q Science > QD Chemistry
ISBN:	9781303214448
Date of First Compliant Deposit:	30 March 2016
Last Modified:	12 Feb 2016 23:13
URI:	https://orca.cardiff.ac.uk/id/eprint/54828

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