Thesis (M.S.)--West Virginia University, 1998. / Title from document title page. Document formatted into pages; contains xii, 99 p. : ill. Includes abstract. Includes bibliographical references (p. 93-99).

Thesis (M.S.)--Brigham Young University. Dept. of Chemistry and Biochemistry, 2008. / Includes bibliographical references (p. 51-54).

In this thesis, firstly, a Pd-catalysed diastereoselective carbocyclisation of allenes with aryl halides or vinyl iodides was designed and developed to form arylative or vinylative spirolactam compounds. High yields and diastereoselectivities were obtained in the presence of Pd₂(dba)₃/dppe and K₂CO₃ in DMSO at 70 &deg;C, particularly when spiropiperidin-2-ones were formed. The method is simple to perform and broad in scope. Having established the diastereoselective methodology for the arylative or vinylative allene carbocyclisation, a Pd-catalysed enantioselective version was developed by using bisoxazolines as chiral ligands. Aryl halides and vinyl iodides were investigated in this carbocyclisation. High yields and enantioselectivities were obtained in the presence of Pd(OAc)₂, a bisoxazoline ligand <strong>L7d</strong> derived from L-isoleucine and Ag₃PO₄ in 1,2-dichloroethane at 70 &deg;C. No olefin isomerisation was observed when cis-vinyl iodides were used. The method is mild, efficient and broad in scope. A palladium catalysed diastereoselective allene carbocyclisation reaction was developed via enamine catalysis and palladium catalysis, which allows for the efficient carbocyclisation of formyl or ketone allenes. Good yields and high diastereoselectivities were obtained in the presence of Pd(OAc)₂ and pyrrolidine in toluene at 60 °C when formyl allenes were investigated. The cyclisation is diastereoselective and can also performed as a catalytic asymmetric reaction by using prolinol derivatives as chiral catalysts. Good yields and high diastereo- and enantioselectivities were obtained in the presence of catalyst <strong>(S)-L19</strong>. Additionally, a boronic acid catalysed ene carbocyclisation of acetylenic dicarbonyl compounds was developed. An attempted transesterification of a &beta;-ketoester substrate bearing a pendent terminal alkyne substituent at the &beta;-position led to the discovery of an efficient 3-nitrobenzeneboronic acid catalysed ene carbocyclisation of acetylenic dicarbonyl compounds. The reaction is easy to perform, efficient, broad in scope and provides a convenient transition metal-free alternative to existing catalytic protocols.

Thesis (Ph. D.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains xiv, 240 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 95-104).

<p><p>The wide-spread occurrence of biologically active nitrogen-containing heterocycles and allylic amines inspired us to develop atom-economical methods for their syntheses.</p></p><p><p>A cationic gold(I) <italic>N</italic>-heterocyclic carbene complex catalyzed the intermolecular hydroarylation of allenes with indoles to form (<italic>E</italic>)-allylic indoles in modest to good yield at room temperature. The protocol was effective for monosubstituted, 1,3-disubstituted, and tetrasubstituted allenes and various indoles.</p> </p><p><p>Platinum(II) bis(phosphine) complexes catalyzed the intermolecular hydroamination of monosubstituted allenes with secondary alkylamines in good yield with selective formation of (<italic>E</italic>)-allylic amines. The scope of the protocol included aryl and alkyl monosubstituted allenes as well as a variety of both cyclic and acyclic secondary alkylamines.</p></p><p><p>The scope of gold(I)-catalyzed intermolecular hydroamination of 1-alkenes with 1-methyl-2-imidazolidinone was expanded to include additional 1-alkenes functionalized with carboxylic acid derivatives. However, a nucleophile screen failed to identify nucleophiles other than cyclic ureas and 2-oxazolidinone that efficiently undergo hydroamination with 1-alkenes. Various carbamates, arylamines, amide derivatives, sulfur-containing amide derivatives, and &alpha;-heteroatom compounds failed to react with 1-octene under gold(I)-catalyzed conditions.</p></p><p><p>A chiral bis(gold) phosphine complex catalyzed the stereoconvergent, intermolecular enantioselective hydroamination of chiral, racemic 1,3-disubstituted allenes with carbamates to form <italic>N</italic>-allylic carbamates in good to high yield with up to 92% <italic>ee</italic>. In addition, enantiopurity experiments suggested the nature of the catalytically active species changes with increasing concentration of <italic>N</italic>-allylic carbamate.</p></p> / Dissertation

Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains xv, 110, [139] p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 102-110).

For the past ten years the Fleming research group has been involved in the research of allene compounds. We have explored the synthesis of allenes as well as several reactions involving allenes, such as oxidation and nitrene addition. Recently, we have explored the synthesis and photochemistry of allenic alcohols tethered to silicon. There are literature examples using allenes in synthesis, but very few examples exist using allenes in photochemical cycloaddition reactions. We have found that a diisopropylallenyloxy(cinnamyloxy)silane derivative undergoes [2+2] photochemical cycloaddition to produce a cyclobutylsilane product when irradiated for 60-75 minutes.

Chemists have always been fascinated by the cumulated diene system of allenes with its extraordinary properties such as the axial chirality of the elongated tetrahedron and a higher reactivity than non-cumulated C-C double bonds. The equilibrium geometry for an allene is linear with orthogonal pairs of substituents. An allene incorporated into a carbocyclic ring of nine or more carbon atoms is relatively unstrained. However, if the ring size is decreased, the linear perpendicular allene will be twisted and bent until, at some point, the energy gained by pi bonding in the two double bonds will be insufficient to offset the increased strain. Furthermore, ring constraints will exert torsion toward a planar arrangement of ligands. Therefore, one of the fundemantal questions is the influence of ring size on the barrier to pi bond rotation. Herein we wish to unveil a review of our research related to desperately seeking for five membered ring allenes such as, cyclopenta-1,2-diene (1) and some of its derivatives, e.g. 2, and 3. Furthermore, we will address a simple, mild and efficient method for the reduction of 1,4-benzoquinones 4 to corresponding hydroquinones 5.

The synthesis of cyclic allenes with eight or less skeletal C-atoms, known as highly strained organic compounds, has for the past decades attracted increasing interest. The first part of study describes an investigation aimed at the incorporation of an allene unit into a natural compound, being &amp / #945 / -pinene, by using &amp / #946 / -elimination method. The two double-bond isomers 310 and 299b were synthesized as key compounds. Treatment of 310 with t-BuOK resulted in the formation of ketone 308 and diene 313. For the formation of 308, the cyclic allene 300 was proposed as an intermediate. Treatment of 299b, with t-BuOK gave arise to the diene 313 and the dimerization product 322. On the basis of density-functional-theory (DFT) calculations on the allene 300 and the alkyne 320, the formation of the latter as the intermediate was excluded. In the second part of study, the stability of endo-carbene 304 was investigated. Previous studies indicated, during the formation of intermediate 264, no exo-carbene 330 structure could be optimized in its free carbene form. At this point, we were curious about the stability of endo-cyclopropylidene 304 not discussed before in literature. First, addition of bromofluorocarbene to anti-7-ethylbenzonorbornadiene (352) was aimed to isolate the endo-adduct 302b. However, no carbene addition reaction was observed caused by pyramidalization on double bond respect to the methoxy derivative, 363b. Therefore, the bromine was introduced to C-7 carbon atom. Treatment of 302a with MeLi in the presence of furan, gave furan adduct 306a confirmed the formation of allene 305a as a reactive intermediate. Theoretical calculations showed endo-carbene 304a was optimized in the free carbene form . However, it readily isomerizes to allene 305a afforded furan adduct 306a.

The first part of study describes an investigation aimed at the incorporation of an allene unit into a natural compound, being alpha-pinene, by using Doering-Moore-Skatteboel method. DFT computations show that both allene product and insertion product can be isolated if the reaction of methyllithium with 3,3-dibromo-2,7,7-trimethyl-tricyclo[4.1.1.02,4]octane is carried out at either low or high temperatures. One insertion product resulting from the intramolecular C-H insertion at the bridge and three allene dimers were isolated when this reaction was carried out at room temperature. In the second part of study, exo- and endo-cyclopropylidene incorporated into benzonorbornadiene were investigated by using theoretical and experimental methods. Theoretical calculations show that the endo-carbene would be stable and undergo some kind of insertion and addition reactions. On the contrary, the exo-carbene is not stable and isomerizes to the corresponding allene structure during the optimization process. For this purpose, the reaction of dibromocarbene and dichlorocarbene with 7-methoxybenzonorbornadiene was achieved to afford gem-dibromocyclopropane and gem-dichlorocyclopropane adducts, respectively. However, they suffer stereoelectronically-controlled ring opening under the reaction conditions to give the ring-expanded allylic dihalides, respectively. On the other hand, gem-bromofluorocyclopropane, obtained by the treatment of 7-methoxybenzonorbornadiene with bromofluorocarbene, provided one of the four possible [2+4] allene adducts upon treatment with MeLi in furan. The exact structure of the adduct has been elucidated on the basis of NMR spectral data. This result confirms the formation of the bicyclic allene as an reactive intermediate. No products were isolated derived from the endo-carbene.