Tetra-n-butylammonium fluoride supported on glass helices was used to generate cyclopropenes in the gas phase from $\beta$-halocyclopropylsilanes using the vacuum gas-solid reaction (VGSR) technique. Bicyclo (4.1.0) hept-1,7-ene (1), bicyclo (4.1.0) hept-1,6-ene (2), and bicyclo (5.1.0) oct-1,8-ene (3) were prepared from the appropriate $\beta$-chlorocyclopropylsilanes.(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI) Compounds 1 and 2 underwent ene reactions to give the same dimer 4. Compound 4 isomerized to 5 via cyclopropene-vinyl carbene rearrangements. Dimerization of 4 led to the cycloaddition adducts 6 and 7 (tetramers of 1).(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI) Treatment of either 4 or 5 with oxygen formed 2-(bicyclo (4.1.0) hept-1-yl)-1-cyclohexenecarboxaldehyde (8) and 1-(bicyclo (4.1.0) hept-1-yl)-cyclohepten-3-one (9).(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI) Hydrogenation 4 and 5 below $-$20$\sp\circ$C yielded products identified provisionally as 10 and 11, respectively. Both 10 and 11 rearranged to meso-1-(bicyclo (4.1.0) hept-1-yl)bicyclo (4.1.0) heptane (12).(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI) Cyclopropene 3 also reacted via an ene reaction to give both dimer and trimer. Tricyclo (5.5.0.0$\sp{1,6}$) decane (13) was prepared by reduction of the butadiene Diels-Alder adduct of 3. Hydrogenation of 3 gave cis-bicyclo (5.1.0) octane and 1-methylcycloheptane.(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI)

A new pyridine synthesis is described. The key step involves a modified Knoevenagel-Stobbe reaction in which the treatment of an alkoxy-dihydropyran with hydroxylamine hydrochloride generates highly substituted pyridine ring systems. Approaches to efficient syntheses of important natural products in including aza-analogs of polynuclear aromatic hydrocarbons, Eupolauramine, and Streptonigrin are explored. Antitumor agents Cystodytin A and B were synthesized in 13 steps from 4-hydroxyethyl cyclohexanone in an overall yield of 7%. This efficient total synthesis involves the new pyridine reaction and a photochemical nitrene insertion as crucial steps. Various approaches are explored toward the total synthesis of antitumor agent Discorhabdin C. The first synthetically useful Paterno-Buchi reaction between benzoquinone and an olefin was discovered. Various applications of this reaction are described, including its use for the synthesis of Discorhabdin C.

Quinone inhibitors are used to prevent polymerization during the storage, transportation and processing of vinyl monomers. If left unchecked, polymerization will decrease the yield of vinyl monomers, result in higher production cost, and even ruin the processing equipment. Most of the published research on such compounds concerns polymer stabilization. The relatively few papers on quinone derivatives as polymerization inhibitors do not lead to a consistent picture of their chemistry. The four most important open questions are: (1) What is the inhibition mechanism? (2) What is the rate constant of these inhibitors with alkyl radicals? (3) Why do the products differ from one report to another? (4) Is the radical scavenging process reversible? All of these questions are important because they determine the effectiveness of inhibitors. We investigated the reaction of four inhibitors (BQ, QM, DPPI and 2,6-di-t-butyl-p-benzoquinone) with alpha-phenethyl radicals 4, which resemble the chain propagating radical in styrene polymerization. The ultimate goal of this research was to better understand the reaction mechanism and rates of alpha-phenethyl radicals with quinoid type radical scavengers.

Benkeser reduction was used to synthesize highly hydrogenated fullerenes, C60H36, C60H38, C 60H40, C60H42 and C60H 44. 1H- and 13C-NMR spectra of HPLC purified fractions show that more highly hydrogenated fullerenes exhibit signals that are shifted upfield. The opposite trend was observed in 3He NMR spectra of the corresponding endohedral helium compounds. The trend in the 3He NMR is attributed to the change in the shape of various hydrogenated fullerenes. Hydrogenated single-walled carbon nanotubes (H-SWNTs) were prepared via the dissolved metal reduction method in liquid ammonia and by Anhydrous Hydrazine in methanol. Spectroscopic analysis of the H-SWNTs shows that hydrogen is covalently attached to the tubes. Scanning Tunneling Microscopy (STM) images of the hydrogenated tubes show bright regions around the circumference of the tube that most likely correspond to the region covered by hydrogen. Precursors of two fulvalenes (calicene and triafulvalene) were prepared by multi-step synthetic procedures. The calicene precursor was obtained by base-induced dehydrobromination, while that of triafulvalene was obtained by a metathesis reaction using first generation Grubbs catalyst. The two precursors are attractive candidates for the parent compounds by using solid fluoride as the dehalosilylation inducing reagent in the final step.

The discorhabdins are a family of chemically and biologically interesting natural products. Previous syntheses of these complex substances have all been very similar; this similarity is limiting to the flexibility of these approaches. We describe a general method which we believe can diverge to make any number of the natural products. This route is based on novel benzoquinone photochemistry followed by an annulation onto a quinone monoketal to give the core structure. This core can then be advanced appropriately to form the natural products.* *Please refer to dissertation for diagrams.

We describe the application of a novel ene-like reaction developed in our laboratory to the facile preparation of benzazocinone and benzazocenone intermediates of the type 3. Thus, ene-like reaction of 1 with 2-methoxypropene furnished adduct 2. This material underwent tandem intramolecular 1,3-dipolar azide cycloaddition and photolysis of the resulting triazoline to give 3. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE MAI) The newly developed avenue to these medium-ring heterocycles should be useful in a total synthesis of the antitumor agent, FR900482, 4. A synthesis of the highly substituted aldehyde 6, which could produce intermediates 5 suitable for the ultimate elaboration into 4 by the new chemistry, has also been developed.(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE MAI)

Chapter 1 discusses recent results in the area of molecular electronics. Molecules have been shown to act as switches and memory components in two different test structures. We have synthesized and tested several molecules using cyclic voltammetry in an effort to fully understand the switching and memory mechanism. Chapter 2 deals with a novel reaction involving HOF. Currently, only limited methodology exists to convert an electron deficient aniline to a nitro group. All known methods involve the use of extremely dangerous reagents and long reaction times. The HOF method developed in our laboratories is extremely efficient yielding the corresponding nitro compounds in high yield in minutes while avoiding hazardous reagents. Chapter 3 discusses the synthesis of nitro containing devices and their utility in memory and switching applications. Several examples are provided including dintitro systems with both the thioacetate "alligator clip" as well as the isonitrile "alligator clip." A bisthiol compound was also synthesized. Chapter 4 is concerned with the quest to discover novel methods of attaching molecules to metal surface. In this vein, work was carried out to synthesize potential devices containing a nitrile group as the method of attachment. Chapter 5 deals with increasing electron flow through molecules making them more conductive. Several phenylene vinylene based compounds were synthesized in an effort to test how the backbone structure of a molecule affects conductance. Chapter 6 discusses the synthesis of isonitrile linking devices as well as devices that contain oxidizable cores. Current silicon technology is based on complementary metal oxide semiconductors (CMOS) that allow two modes of switching. Molecular devices that contain oxidizable cores may be the equivalent of CMOS when combined with devices that operate via reduction. Chapter 7 is concerned with materials that inhibit corrosion while allowing conduction in interconnect applications. Several polymeric systems have been examined and have shown to be ideal for this type of application.

The product mixture of the lithium Birch reduction of C60 is analyzed. C60H36 is identified as the major product; C60H32, C60H38 and C60H 40 are identified as minor products. The product mixture is separated into four fractions by high pressure liquid chromatography. 3He NMR spectra are obtained for the fractions by reduction of 3He C 60 and the 3He chemical shifts are compared to calculated values. The dihydroanthracene reduction of C60 is shown by high pressure liquid chromatography to produce a single major isomer of C 60H36. A comparison of the 3He NMR spectra determines that the major dihydroanthracene C60H36 isomer has C3 symmetry and that this isomer is also obtained by the Birch reduction of C60. C60H38, C60H 40 and C60H42 are synthesized by the lithium-ethylenediamine reduction of C60H36. 1,2-C70H 2 is synthesized by anhydrous hydrazine reduction of C70.

New methods for covalent functionalization of single wall carbon nanotubes (SWNTs) have been developed through fluorinated nanotube material. Nanotube material that had been reacted with elemental fluorine to render a C 2F stoichiometry has been further functionalized with organolithium and Grignard reagents. The resulting products show distinct solutions properties from both the original pristine nanotube material and the fluorotubes. Routes to solubilization of nanotubes in water have been established through non-covalent interactions with polystyrene sulfonate and polyvinyl pyrollidone. SWNTs which are characterized with absorption, Raman, and fluorescence spectroscopies have been rendered soluble in water in concentrations substantially higher than those achievable with surfactant stabilized tubes. The spectroscopic nature of SWNT material is strongly influenced by non-covalent interactions of the tubes with their local microenvironment. These functionalized or solublized SWNTs can be chemically manipulated as organic macromolecules. In this way, high performance liquid chromatography (HPLC) has been shown to be a useful tool in the separation of nanotubes from one another.

The goal of this research was to explore new routes for the construction of viridin- and xestoquinone-related classes of natural products along with similar non-natural products. The four main targets being addressed are viridin, wortmannin, xestoquinone and halenaquinone. These compounds possess a wide array of biological activities including inhibition of topoisomerase I and II, phosphatidylinositol 3-kinase (PI 3-kinase), protein tyrosine kinase (PTK), and human epidermal growth factor (EGF) kinase. Various kinases as well as topoisomerases affect disease states involving aberrant cell proliferation. The common furanosteroid backbone of these natural products allows for a unified strategy in their construction. The B,C,D-ring systems will be synthesized by a Diels-Alder approach, and the A,B,E-ring systems will be constructed using transition-metal mediated couplings. The core of each molecule, the B-ring, (amino aldehyde 27) is a known compound and can be synthesized in enantiomerically pure form. In the course of elaborating the core of these natural products, we developed a methodology for the diastereoselective addition of organozincs to beta-amino aldehydes. Other achievements include assembly of the B,C,D-rings in xestoquinone and halenaquinone, and annulation of a furan which can be applied in the synthesis of all four natural products. With regard to stereochemistry, the stereocenter in xestoquinone and halenaquinone has been set, the A and B-ring stereocenters in wortmannin have been correctly synthesized, and all but one stereocenter in viridin has been set correctly. The long term goal is to apply methodologies developed while pursuing the synthesis of one natural product to the other furanosteroids. After this is accomplished we will address the assembly of derivate compounds utilizing the B,C,D-ring system of one molecule, followed by annulation of the A,E-rings of another molecule. This thesis represents the founding work in this area within the Behar group.