Thesis--M. Phil., University of Hong Kong, 1978. / Copy 2 xerox copy of typescript. Typescript.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

This thesis describes the synthesis and intramolecular cycloaddition products of azides tethered to olefins bearing a heteroatom in an attempt to access a proposed triazolium intermediate 77. Chapter 1 covers the synthesis and reactivity of simple di- and trisubstituted azidoalkyl enol ethers. These substrates were found to provide isolable 1,2,3-triazoline products, but displayed a propensity to aromatise to 1,2,3-triazoles upon ionisation. Difficulties in synthesising fully-substituted azidoalkyl enol ethers have precluded a detailed study in this project, though a bias towards α-alkoxy imine formation was suggested. Chapter 2 covers the chemistry of azidoalkyl vinyl bromides. Simple vinyl bromide substrates were found to yield 1-azadienes upon thermolysis, presumably via the dehydrobromination of an α-bromo imine intermediate in situ. In Chapter 3, a brief diversity-oriented synthesis (DOS) campaign was undertaken to demonstrate the potent reactivity of 1-azadiene substrates. 1-Azadienes were found to be versatile intermediates, and a small DOS library was built by exploiting several key reactivity modes. In Chapter 4, two miscellaneous routes towards the desired triazolium intermediate are discussed, and finally an Appendix chapter deals with an attempted total synthesis of salinosporamide C.

A number of privileged starting materials based on aryl halide frameworks have emerged that allow access to a variety of different heterocyclic scaffolds through judicious choice of reaction conditions. This work describes efforts to develop and extend the utility of two of these general heterocycle precursors - ortho-(haloalkenyl)aryl halides A and α-(ortho-haloaryl) ketones B - in conjunction with cascade reactions involving the construction of key carbon-heteroatom bonds via palladium or copper catalysis. Chapter 1 entails an overview of the development of palladium- and copper-catalysed carbon-heteroatom bond forming processes. The application of these processes in heterocycle synthesis using ortho-(haloalkenyl)aryl halide and ortho-haloacetanilides/ α-(ortho-haloaryl) ketone precursors is also described. Chapter 2 focuses on the development of a two-step synthesis of cinnolines using ortho-(haloalkenyl)aryl halides via intermediate protected dihydrocinnoline derivatives C. Chapter 3 demonstrates how the inherent reactivity of protected dihydrocinnoline derivatives C can be harnessed to provide access to functionalised products. A brief target synthesis of a pharmaceutically-relevent cinnoline is also described. Chapter 4 details attempts to develop a novel synthesis of benzothiophenes D from both ortho-(haloalkenyl)aryl halide and α-(ortho-haloaryl) ketone precursors.

The aim of this project was to develop new catalytic methods to control asymmetry in electrocyclic reactions, and to apply these methods to generate complex molecules. Initial efforts were directed towards the catalysis of anionic 8π electrocyclizations (Chapter 2 and Figure i). 8π electrocyclization was not achieved due to issues with alkene geometry and anion stability. Our efforts were then directed towards using phase-transfer catalysis to generate complex polycyclic compounds via a cascade electrocyclization-1,4-addition (Chapter 3 and Figure ii). Pyrrolidines and indolizidines were generated in excellent yield from simple starting-materials with high levels of stereocontrol. Finally, we investigated the catalysis of a 6π [1,6] electrocyclization to generate dihydroquinolones (Chapter 4 and Figure iii). A novel BINOL-derived copper(II) catalyst was developed, and afforded dihydroquinolones directly from their amine and aldehyde precursors with good yields and enantioselectivities.

Chapter 1 is a brief literature review of the most recent progress in the area of C-H functionalization via palladium catalysis. This covers the functionalization of electron deficient arenes and heterocycles with alkenyl and alkyl halides both using inter- and intra-molecular reactions. The chapter also contains an overview of recent work from the Willis group. Chapter 2 presents the functionalization of electron deficient arenes and alkenyl bromides using palladium catalysis, as well as the use of statistical analysis software for optimizing the cross-coupling reaction. Chapter 3 describes the cross-coupling of substituted benzoxazoles, benzothiazole and benzimidazole with a range of alkenyl iodides using palladium catalysis. The reaction can tolerate both (E) and (Z) disubstituted alkenes and tri-substituted alkenyl iodides, with retention of the double bond geometry. Chapter 4 details the synthesis of sultams via an intramolecular C-H functionalization using palladium catalysis. The chapter covers the optimization of the starting material synthesis as well as the cross-coupling reaction. We can access the sulfonamides from cyclohexenone and were able to incorporate a large range of substitution patterns (Scheme 3). Finally, Chapter 5 contains all the experimental details, general considerations and compound data. All the NMR spectra of novel compounds can be found in the appendix.

This work describes the extension of rhodium-catalysed intermolecular hydroacylation to encompass some tandem catalytic processes, wherein a further catalytic process is enacted on the product of an intermolecular hydroacylation reaction in “one pot”. Chapter 1 entails an overview of the development of hydroacylation chemistry, with a focus on the different types of catalytic systems which have been used to facilitate this transformation. A brief description of some precedented examples of tandem catalytic processes which include a hydroacylation reaction is also included. Chapter 2 describes the intermolecular hydroacylation of chelating aldehydes and propargylic alkynes to form γ-hydroxy-α,β-enones, and their subsequent acid-catalysed cyclisation to form substituted furans in a "one-pot" procedure. Additionally, a tandem intermolecular hydroacylation/double-bond isomerisation protocol for the synthesis of 1,4-dicarbonyl compounds is detailed, and the subsequent transformation of this class of compounds to heterocycles is included. Chapter 3 focuses on the development of tandem catalytic hydroacylation/reductive processes, wherein a hydroacylation product undergoes a reduction which is catalysed by the hydroacylation catalyst. Chapter 4 describes an attempt to utilise the rhodium-catalysed conjugate addition of arylmetal species to enomes to create a tandem alkyne hydroacylation/conjugate addition process. Chapter 5 encompasses the use of a small range of different solvents in rhodium-catalysed hydroacylation, in an attempt to find higher-boiling alternatives to acetone and a "green" alternative to the commonly used DCE.

<strong>Chapter 1. Introduction</strong> Scientific background on the development of homogeneous palladium-catalysed cross coupling reactions, focusing on the &alpha;-arylation reaction of enolates and its application to the synthesis of heteroaromatic compounds. The classical syntheses of isoquinolines are discussed, followed by an account of modern methods for their synthesis, including the recent &alpha;-arylation-based methodology developed by the Donohoe group. <strong>Chapter 2. Results and Discussion</strong> 2.1 Studies towards the development of a palladium-catalysed, C–H activation-based &alpha; arylation reaction of ketones, resulting in a C–H bromination/&alpha;-arylation sequence for the synthesis of isoquinolines and isoquinoline N-oxides. 2.2 The one-pot, four component coupling of a ketone, an acetal protected ortho-bromobenzaldehyde or ketone, an electrophile, and an ammonia source is described. This protocol, which ultimately provides C4 functionalised isoquinolines, is later extended to a novel &alpha;,&alpha; heterodiarylation protocol to furnish C4-aryl isoquinolines. 2.3 It is shown that the synthesis of 3 aminoisoquinolines can be achieved via the &alpha; arylation of nitriles. tert-Butyl cyanoacetate can act as a substitute for primary alkyl nitriles, with sequential &alpha;-arylation, in situ functionalisation, decarboxylation and cyclisation reactions provide C4 functionalised 3 aminoisoquinolines. 2.4 The synthetic utility of the &alpha; arylation based methodology for isoquinoline synthesis is exemplified by the total synthesis of the alkaloid berberine in 68% yield over five steps. This is followed by syntheses of pseudocoptisine, palmatine, dehydrocorydaline, and an unnatural fluorine containing analogue, in yields of 46%, 73%, 60% and 37%, respectively. 2.5 Finally, preliminary investigations demonstrate the utility of palladium-catalysed enolate arylation in the synthesis of &beta;-carbolines.