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Thesis advisor: James P. Morken / This dissertation details recent developments in palladium catalyzed carbon-carbon bond formation reactions with two areas of focus: the palladium catalyzed branched and enantioselective allyl-allyl cross-coupling, and the palladium catalyzed carbonylative conjugate addition. Allyl-allyl cross-coupling presents an opportunity to synthesize 1,5-dienes, a scaffold that resembles subunits of terpenes, a critical building block in nature. Chapter I provides an overview of the developments in the allyl-allyl cross-coupling area. Chapter II, III, and IV detail strategies to construct complex substituted asymmetric 1,5-dienes through branched selective and enantioselective allyl-allyl cross-coupling. In chapter V, the palladium catalyzed carbonylative conjugate addition is discussed. This method enables the synthesis of 1,4-dicarbonyl compounds in an atom economical and environmentally friendly fashion, and provides a direct access to five membered heterocycles, a valuable class of chemicals in medicine. / Thesis (PhD) — Boston College, 2014. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Thesis (Ph. D.)--University of Chicago, Department of Chemistry, 2002. / Includes bibliographical references. Also available on the Internet.

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Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 88-89).

The synthesis of amines bearing an adjacent quaternary stereocentre is challenging. Work within our group has demonstrated that the intramolecular transfer of an aryl group within a lithiated benzylic urea is possible. Subsequent cleavage of this urea moiety allows the synthesis of chiral aryl amines bearing quaternary stereocentres. This thesis details investigations into the lithiation of allylic and vinylic ureas. A sequential transformation of allyl ureas into diarylallyl ureas has been developed, a reaction that can be carried out enantioselectively using chiral lithium amides. Deprotection of the urea allows for the isolation of amines bearing highly substituted centres. It has been shown that the use of the acid-labile vinylic protecting groups allows the corresponding Cbz protected diarylallyl amines to be synthesised. Investigations have demonstrated that these analogues can be converted into otherwise synthetically challenging diarylglycine derivatives. During these investigations it has also been shown that carbolithiation of vinyl ureas is possible. The ureas formed from this tandem β-alkylation/α-arylation sequence can then be converted to their highly substituted amine counterparts in good yields. A range of allylic ureas has been investigated; their synthesis and reactivity upon lithiation are discussed within this thesis.

Thesis advisor: James P. Morken / This dissertation details the development, application and study of new palladium-catalyzed carbon-carbon bond forming strategies that generate synthetically useful enantioenriched small molecules. Controlled by a bidentate phosphine ligand, these transformations are thought to operate through a unique 3,3'-reductive elimination that leads to high regio- and stereoselectivity. Specifically, Chapter 1 introduces background on prior work that led to the first allyl-allyl coupling to deliver branched 1,5-dienes, and presents new computational studies on the origins of regioselectivity with mono- and bidentate ligands. Building on these studies, Chapter 2 describes the development of a diastereoselective allyl-allyl coupling of substituted allylboron reagents with allylic chloride electrophiles. To extend the scope of allyl-allyl coupling, Chapter 3 details further reaction optimization and mechanistic studies that have allowed for increasingly congested bond formations. In Chapter 4, a related allyl-propargyl coupling to give enantioenriched 1,5-enynes through stereospecific reactions and kinetic resolution is presented. These developments are accompanied by laboratory and computational data that provide a deeper understanding of reaction mechanisms and the origins of regio- and stereoselectivity. / Thesis (PhD) — Boston College, 2014. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

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The palladium-catalysed asymmetric allylic alkylation is a mild and versatile bond forming reaction between a nucleophile and allylic electrophile. The wide scope of nucleophiles used, and the high regio- and stereoselectivity obtainable renders this transformation an important technique in enantioselective synthesis. The mechanism is known to go via a key palladium π-allyl intermediate, followed by nucleophilic addition occurring at the terminal allylic carbon. Both the formation of the palladium π-allyl, and the nucleophilic addition to generate the alkylated product and palladium(0) proceed with high levels of inversion of stereochemistry, and both provide an opportunity for the induction of stereochemistry. However in the case of ligand controlled nucleophilic addition memory effects have been observed. The epimerisation of the palladium π-allyl before nucleophilic attack is key to achieving high levels of selectivity when racemic starting materials and chiral ligands are employed. Previous work in the Lloyd-Jones group has determined that prolonging the lifetime of the palladium π-allyl species, either by the use of weakly coordinating counter ions or slow addition of the nucleophile reduces this memory effect, however increasing the rate of epimerisation would have a result in a similar effect. One of the mechanisms resulting in the epimerisation of the palladium π-allyl species is mediated by palladium(0), however the details of the mechanism are not well understood. We describe the synthesis of a diastereotopic palladium cyclohexenyl ester and labelled the complex with 108palladium and d3 at the cyclohexenyl ester. Using simultaneous 31P NMR and mass spectrometry, we have acquired strong evidence against mechanisms involving a single electron transfer, as proposed by Stille, of formation of a dinuclear palladium(I) species followed by an inversion event, and we have gained evidence supporting the direct nucleophilic addition of the palladium(0), resulting in inversion of stereochemistry. The differences in rates of nucleophilic attack involving monodentate and bidentate phosphine ligands on both the palladium I-cyclohexenyl ester have also been explored. Throughout the mechanistic investigation, it was noted that the 31P NMR spectroscopy experiment used gave non-quantitative results, and in fact the differences in quantification of the species varied with the spectrometer used. We also describe our investigations into where these differences arise from and an optimum set of parameters for quantitative 31P NMR spectroscopy. The conclusions are also applicable to other heternuclear NMR spectroscopic experiments.