Thesis (Ph.D.) -- McMaster University, 2007. / Supervisor: Shiping Zhu. Includes bibliographical references.

The Stille reaction has established itself as one of the two most general and most selective palladium-catalyzed cross-coupling reactions, along with the Suzuki cross-coupling of organoboron compounds. The Stille coupling of α-alkoxystannanes is a relatively unexplored area. A previous study showed that an α-alkoxyalkylstannane could be coupled with benzoyl chloride with retention of configuration. However, our group has recently shown that Stille couplings of sulfonamidobenzylstannanes proceeds with inversion of configuration. In order to determine whether the Stille coupling reaction of α-alkoxybenzylstannanes proceeds with inversion or retention, the stereochemistry in the Stille reaction of α-alkoxybenzylstannanes was studied. Optimized conditions for Stille coupling of α-alkoxybenzyl-tributylstannanes with benzoyl chloride were developed: highest yields were observed using Pd2dba3 and PPh3 in toluene. Enantiomerically enriched α-hydroxystannanes were obtained via chromatographic resolution of diastereomeric carbamate derivatives. An X-ray crystal structure was obtained for the 3,5-dinitrobenzoate derivative of (S)-1-hydroxyphenylmethyl-trimethylstannane. Stille coupling (cat. Pd2dba3, PPh3, toluene) of the corresponding acetate with benzoyl chloride provided the acetate of (R)-benzoin thus establishing retention of configuration under these reaction conditions.

The Stille reaction has established itself as one of the two most general and most selective palladium-catalyzed cross-coupling reactions, along with the Suzuki cross-coupling of organoboron compounds. The Stille coupling of α-alkoxystannanes is a relatively unexplored area. A previous study showed that an α-alkoxyalkylstannane could be coupled with benzoyl chloride with retention of configuration. However, our group has recently shown that Stille couplings of sulfonamidobenzylstannanes proceeds with inversion of configuration. In order to determine whether the Stille coupling reaction of α-alkoxybenzylstannanes proceeds with inversion or retention, the stereochemistry in the Stille reaction of α-alkoxybenzylstannanes was studied. Optimized conditions for Stille coupling of α-alkoxybenzyl-tributylstannanes with benzoyl chloride were developed: highest yields were observed using Pd2dba3 and PPh3 in toluene. Enantiomerically enriched α-hydroxystannanes were obtained via chromatographic resolution of diastereomeric carbamate derivatives. An X-ray crystal structure was obtained for the 3,5-dinitrobenzoate derivative of (S)-1-hydroxyphenylmethyl-trimethylstannane. Stille coupling (cat. Pd2dba3, PPh3, toluene) of the corresponding acetate with benzoyl chloride provided the acetate of (R)-benzoin thus establishing retention of configuration under these reaction conditions.

No description available.

Multifragmentation reactions have been used to study many of the complexities of the nucleus. Recently, work has been done to tie observables from multifragmentation reactions to astrophysical observables used in supernova explosions. To make this connection, it is necessary to have a highly excited, equilibrated system. The creation of a highly excited system is done for this dissertation by the reaction of one projectile, ³²S, on three targets, ¹¹²⁾¹²⁴Sn and ^natAu at 45 MeV/nucleon. The forward array using silicon technology, FAUST, was used to collect the fragments produced from the excited projectiles. The motivation for this study was to isotopically identify the fragmenting source and to understand the relationship between its N/Z and the resulting fragmentation. This can then be used to constrain theoretical models which predict the evolution of supernova explosions. Using an isotropically identified source, the resulting fragmentation of the projectile has been studied. It is shown that there are dependencies on the fragment mass distribution, fragment charge distribution and source excitation energy from the source N/Z. Looking more specifically at the fragments produced, it was found that there is a parallel velocity anisotropy in the particle emission. This anisotropy is found to be a direct result of the presence of an external Coulomb field. Using DIT+SMM theoretical calculations, the anisotropy has been found to be dependent on the distance at which the projectile breaks up from the target (external Coulomb field). As the parallel velocity is related to the angle of emission, it is of interest to extract out the average kinetic energy of each isotope to determine if there are differences in the average kinetic energy by the angle of emission. It is found that the average kinetic energy is dependent on the emission angle in the quasi-projectile frame. Because of this, care should be taken when comparing between systems to ensure similar regions are being compared. However, the observation that the average kinetic energy changes as a function of the emission angle is not dependent on the presence of an external Coulomb field. Using DIT+SMM calculations, the differences between the average kinetic energy from different angles of emission are seen even when no external Coulomb field is present. These changes are attributed to the angular momentum. In all cases, a statistical framework, supplied by DIT+SMM calculations, can explain many phenomena seen from a fragmenting nucleus. However, the accuracy of the model varies when moving from a neutron-poor to a neutron-rich source.

Thesis (M.S.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 22, 2008) Includes bibliographical references.

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1904. / The entire thesis text is included in file. Typescript. Illustrated by authors. Title from title screen of thesis/dissertation PDF file (viewed December 28, 2009)

Thesis (Ph. D.)--School of Chemistry and Biochemistry, Georgia Institute of Technology, 2004. Directed by Andrew Lyon. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (M. Phil.)--University of Hong Kong, 1984. / Caption title.