Feeding of [3-¹³C, 2-¹⁵N]arginine, 38a, unequivocally established that the β-
arginine moiety of blasticidin S, 1, was formed from α-arginine by an intramolecular
migration of the α-amino group to the β- position. Further feedings using chirally
deuteriated arginines 38e and 38f revealed that the aminomutase process occurred with
inversion of...
Three approaches toward the core of halichlorine and pinnaic acid are described. The first approach entails a racemic transannular nitrone-olefin [3+2] cycloaddition from nitrone 238. Construction of the nitrone 238 began with aldehyde 241. Another key feature in this route involved a ring-closing metathesis for the formation of a 14-membered...
In situ reduction of hydrido-tris-(3,5-dimethylpyrazolyl)borato(trioxo) rhenium(V) with triphenylphosphine or triethylphosphite leads to a reactive rhenium(V) species that catalytically deoxygenates epoxides at 75-105°C. The reaction is stereospecific, except for trans- and cis-butene oxide which formed minor amounts of the opposite isomer. A variety of different functional groups were tolerated and even...
The photohydrodebromination of brominated paracyclophanes was studied to
help elucidate the possible mechanistic pathways leading to product for
bromoarenes in general. Several brominated [2.2]paracyclophanes were studied to
determine the effect of substitution patterns on this reaction. [2.2]Paracyclophanes
were chosen for this study in order to investigate possible intramolecular excimer
formation...
The method of gas-phase electron diffraction is a very useful tool for determining
the geometry of a molecule in the gas-phase to a high degree of accuracy. In this thesis,
the structures of tropone and tropolone, which are similar molecules that are both based
on a 7-carbon ring, were investigated...
A multielement spectrometer has been developed for the simultaneous determination of four elements by atomic absorption (AA) or atomic fluorescence (AF). The spectrometer is based on a multiple exit slit monochromator and uses a mirrored funnel to direct light from the various exit slits to a single photomultiplier. There are...