Thesis (Ph. D.)--University of Wisconsin--Madison, 1952. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record.

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The aim of this work was to investigate palladium-catalysed cyclisations of bromoenynamides in the synthesis of amidodienes, which on further reaction or oxidation can lead to a diverse range of heteroaromatic systems. Building upon work within the Anderson group on the palladium-catalysed cyclisations of bromoenynes, we have been able to successfully apply a palladium-catalysed carbopalladation/Stille coupling/electrocyclisation cascade to bromoenynamides and then further develop this to incorporate a Suzuki coupling, leading to bicyclic amidodienes which can undergo selective oxidation to a range of heteroaromatics including indolines, indoles, tetrahydroquinolines and benzazepines. During the investigations into the cascade cyclisation, a reductive cyclisation was discovered which enabled access to a range of monocyclic amidodienes. These could subsequently be subjected to a series of Diels-Alder cycloadditions (thermal, Lewis acid-catalysed, arynes) and oxidations to afford a complimentary range of heteroaromatic systems. Whilst this methodology was successful with bromoenynamides, extension of its application to bromoenynhydrazides, with the hope of accessing a relatively unusual range of heteroaromatic structures including indazoles, cinnolines and diazepines, proved to be more problematic. Finally, expansion of the cascade methodology into a fully intramolecular cyclisation, enabled studies towards the synthesis of the trikentrin family of natural products to be conducted.

1,2-Dioxines are a specific class of cyclic peroxide that are both prevalent in nature and important synthetic building blocks. To date, much of the chemistry involving 1,2-dioxines is concerned with cleavage of the weak peroxide bond, providing a convenient method for the incorporation of 1,4-oxygen functionality into molecules. Comparatively little attention has been directed towards transformations of the alkene unit contained within 1,2-dioxines, which is the focus of this thesis. The synthesis of a broad range of diversely functionalised 1,2-dioxines from commonly available starting materials is presented. Subsequently, the osmium catalysed dihydroxylation of 3,6-disubstituted 1,2-dioxines was investigated, furnishing novel peroxy diols in high yield and with excellent diastereoselectivity. The peroxy diols were then reduced, affording stereospecific tetraols and higher polyols, including the rare sugar allitol. In addition, homolytic ring-opening of the 1,2-dioxanes was examined, providing a new route to polyhydroxylated furanoses, highlighted by the synthesis of the natural keto-sugar psicose. Several 4-substituted 1,2-dioxines were also dihydroxylated, followed by reduction of the peroxide bond, providing a convenient route to branched erythritol derivatives, including the important plant sugar 2-C-methyl-erythritol. The cobalt catalysed ring-opening of the peroxy diols produced novel erythrose derivatives in high yield. In addition, the triphenylphosphine induced ring contraction of the peroxy diols is presented, which allowed for the synthesis of novel dihydroxylated tetrahydrofurans in excellent yield. Asymmetric dihydroxylation of the achiral 4-substituted 1,2-dioxines was explored, furnishing optically enriched peroxy diols with varying enantioselectivity depending on the substrate. The synthesis of novel alkyl and aryl branched erythrono-γ-lactones via oxidation of lactols derived from the acetonide protected peroxy diols is also documented. The utility of this sequence is illustrated by the preparation of potassium 2,3,4-trihydroxy-2-methylbutanoate, a leaf-closing substance of Leucaena leucocephalam. Additionally, γ-lactones were prepared from epoxy hydroxy ketones derived from epoxy-1,2-dioxanes, facilitated by a Baeyer-Villiger lactonisation protocol. The requirements and limitations of this procedure are discussed. The proposed and attempted synthesis of other lactones from 1,2-dioxines was also examined. Finally, several other general alkene transformations were investigated on 1,2- dioxines including: halo-hydrin formation, phenylselenyl chloride addition, aminohydroxylation, cyclopropanation, and aziridination, allowing for the preparation of several new classes of functionalised 1,2-dioxines. In summary, the work presented in this thesis establishes clear and efficient methodology towards several interesting and useful sugar-type core structures from modified 1,2-dioxines. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1313493 / Thesis (Ph.D) -- University of Adelaide, School of Chemistry and Physics, 2008

The work presented in this thesis involves new transformations of azacycles, focusing on the introduction of functionality α-to N. α-C-H functionalisation on an azetidine has been a long-standing challenge, with N-protecting/activating groups that work well in the higher and lower azacyclic systems not viable. A recent breakthrough in the Hodgson group showed the rarely used N-thiopivaloyl group was effective for α-deprotonation– electrophile trapping on azetidines, but was not without limitations concerning harsh removal conditions and scope for further substitutions. This thesis describes efforts to overcome these issues by development of a new protecting/activating group for N, t-butoxythiocarbonyl (Botc).

A presente tese apresenta: I - Uma revislo bibliográfica sobre os adutos de Diels-Alder entre benzoquinonas 2-mono-substituídas ou benzoquinona não-substituída e ciclopentadieno; II - Uma visão mecanística, de literatura, sobre as reações de ciclo-adição; III - A síntese, por nós efetuada, de uma série de adutos de Diels-Alder entre ciclopentadieno e benzoquinonas 2-mono-substituídas por cloro, bromo, ou ainda, substituintes contendo nitrogênio, oxigênio, enxofre ou selênio; IV - O estudo que empreendemos sobre a fotociclização dos adutos acima mencionados. Na obtenção dos adutos, foram empregados dois métodos distintos: a reação de Diels-Alder e a substituição do halogênio por nucleófilos, nos adutos halogenados. Nove adutos inéditos foram isolados e caracterizados. A estereoquímica dos treze adutos preparados foi esclarecida por RMN de 13C e de 1H. O estudo da fotociclização dos adutos visava dois aspectos: sintético, para a obtenção de compostos-gaiola, e mecanístico. Foram isolados e caracterizados sete novos compostos-gaiola. Foi sugerido o mecanismo das referidas fotociclizações, através das determinações dos rendimentos quânticos e dos resultados de voltametria cíclica. Foi, também, fornecida uma possível explicação para a falta de reatividade fotoquímica de alguns adutos. / This thesis contains: I - A literature review about cyclopentadiene Diels-Alder adducts of benzoquinone and its 2-mono-substituted derivatives; II - A mechanistic overview of cycloaddition reactions; III - The synthesis of a series of Diels-Alder adducts of cyclopentadiene and 2-mono-substituted (by chloro-, bromo- or groups containing nitrogen, oxigen, sulfur or selenium) benzoquinones; IV - The investigation about the photocyclization of the same adducts. Two different methods were employed for the obtention of these adducts: either the Diels-Alder reaction, or the substituition of the halogen by nucleophiles, in the halo-containing adducts. Nine previously unreported adducts were isolated and characterized. The sterochemistry of the thirteen adducts prepared was determined through 13C and 1H NMR. The investigation about the photocyclization of the adducts had two main objectives: the synthesis of the corresponding cage-compounds and the elucidation of the photocyclization\'s mechanism. Seven new cage-compounds, previously unreported, were obtained and characterized. Quantum yield determinations and cyclic voltammetry data led to the proposition of a mechanism for the photocyclization reactions. An explanation for the lack of photoreactivity presented by some adducts was also furnished.

Neste trabalho foi preparada uma série de sais de piridínio, com subsequente investigação da sua atividade catalítica e indução assimétrica em reações de adição de Michael e alquilações de metilenas ativas. Os sais de piridínio foram preparados pela reação de tetrafluorborato de 2,4,6-trifenilpirílio e 2,4,6-trimetilpirílio com aminas, aminoálcoois e/ou aminoácidos. As reações em que se efetuou o teste catalítico destes sais foram: a) adição de cianoacetato de etila, N-acetamidomalonato de dietila e nitrometano à chalcona e de tiofenol à 2-ciclohexenona; b) alquilação de cianoacetato de etila e de fenilcianoacetato de etila com cloreto de benzila. Os sais de piridínio testados atuaram como catalisadores nas alquilações de metilenas ativas e nas adições de Michael, com exceção da reação de N-acetamidomalonato de dietila com chalcona. No que tange à eficiência como indutores de assimetria, foram feitas reações comparativas entre os sais de piridínio quirais, o brometo de N-benzil-N-metilefedrínio ou o cloreto de N-benzilquinínio, sendo que os catalisadores por nós sintetizados se mostraram menos eficientes. A conformação preferencial de três sais de piridínio, em que a cadeia alquílica ligada ao átomo de nitrogênio possue um substituinte aromático, foi determinada através de experimentos de NOE-diff. Para dois destes sais há evidências da formação de complexos de transferência de carga intramolecular. A atividade catalítica e a indução assimétrica destes três catalisadores foi interpretada com base no estudo conformacional acima mencionado. / In the presente work, a series of pyridinium salts was prepared and their catalytic activity evaluated, as well as their ability to induce asymmetry in Michael additions and alkylation of organic carbon acids. Such pyridinium salts were prepared by reacting 2,4,6-triphenyl or 2,4,6-trimethylpyrilium tetrafluoroborates with amines, α-aminoalcohols or α-aminoacids. The catalytic activity of the prepared salts was evaluated in the folIowing PTC reactions: a) Michael addition of ethylcyanoacetate, diethyl N-acetamidomalonate or nitromethane to chalcone and of thiophenol to 2-cyclohexenone; b) alkylation of ethylcyanoacetate or ethyl phenylcyanoacetate, using benzyl chloride as eletrophile. In alI cases, except 1,4-addition of diethyl N-acetamidomalonate to chalcone, the prepared pyridinium salts displayed catalytic activity although with inferior asymmetric induction efficiency as compared to the classicalIy used efedrinium and quininium salts. The preferencial conformation of three pyridinium salts bearing aromatic rings in the nitrogen substituent aliphatic chain was determined by NOE diff experiments. In two cases some evidences for charge transfer was provided by uv measurements. The catalytic result and the asymmetric induction were interpreted on the basis of the well accepted substrate/catalyst interaction model and conformational analysis data.

DICLORO-α-(ALQUILTELURO)CETONAS Estudou-se a reação entre quantidades equimolares de cetonas ou éteres enólicos de silício de cetonas e tricloretos de alquil telúrio, obtendo-se dicloro-α-(organil) cetonas. Em todos os exemplos efetuados obtiveram-se bons resultados apenas nas reações com éteres enólicos de silício. TELURETOS VINíLICOS TRISSUBSTITUíDOS Neste trabalho desenvolvemos um método de preparação de teluretos vinílicos trissubstituídos, obtidos através da reação de adição de tricloreto de aril telúrio e tetracloreto de telúrio a acetilenos aromáticos e alifáticos, levando aos dicloretos de aril-2-clorovinila de configuração Z. A redução da ligação Te-Cl dos dicloroteluro compostos obtidos, levando aos teluretos correspondentes pode ser efetuada em alto rendimento pela reação com um equivalente de NaBH4. A halogenodeteluração destes teluretos vinílicos trissubstituídos foi possível reagindo-os com N-bromosuccinimida/cloreto de alumínio, obtendo-se bromocloroalquenos em rendimentos moderados. 1,1-DIHALO-2-(FENILSELENO)CICLOPROPANOS Outro tópico abordado foi a preparação de 1,l-dihalo(fenilseleno)ciclopropanos, por meio da adição de dihalocarbenos, gerados sob condições de transferência de fase, a selenetos vinílicos de configuração Z ou E. A adição ocorreu com retenção de configuração da ligação olefínica. Também foram preparados, empregando-se a mesma metodologia acima mencionada, selenociclopropanos tri- e tetrassubstituídos. / α- DICHLORO-(ORGANYLTELLURO)KETONES The reaction of equimolar amounts of ketones or ketone trimethylsilylenol ethers with aryltellurium trichlorides in boiling benzene produces α - dichloro-(aryltelluro) ketones in good yields. The reaction with aliphatic tellurium trichlorides give good results only with ketone silyl enol ethers; reaction with ketones gives low yields of the α-dichloro-(organyltelluro)ketones. VINYLIC TELLURIDES (p-Methoxyphenyl)tellurium trichlorides and tellurium tetrachloride react with terminal acetylenes to give 1-chloro-1-organyl-2-[dichloro(p-methoxyphenyl)telluro] ethenes of Z configuration in good yields. The diorganyl tellurium dichlorides are reduced to the corresponding tellurides with sodium borohydride. Halogenodetelluration of these trisubstituted vinylic tellurides was possible by reaction with N-bromosuccinimide/aluminium(III) chloride, producing the correspondent bromochloroalkenes in good yields. 1,1-DIHALO-SELENOCYCLOPROPANES Selenocyclopropanes were prepared by the addition of dihalocarbenes, generated under phase transfer conditions to Z and E disubstituted vinylic selenides. The addition occurs with retention of configuration of the olefinic bond. By employing the above mentioned methodology it was possible to prepare tri- and tetrasubstituted selenocyclopropanes.