Thesis (Ph.D., Chemistry) - University of Idaho, 2015 | In this dissertation we offer a discussion on the development of three novel oxidation methods. Chapter 1 presents the dehydroaromatization of N-heterocycles using vanadium pentoxide. Tetrahydrocarbazole is readily aromatized to carbazole by vanadium pentoxide in refluxing acetic acid under both stoichiometric and catalytic conditions. Eight other substrates are similarly aromatized in good yields. An extended application of this methodology is the efficient one-pot Fischer indole synthesis and dehydrogenation to form carbazoles.
Chapter 2 describes a unique process for 1,2-dibromination of olefins using aqueous HBr and dimethyl sulfoxide. This novel methodology offers a simple, inexpensive, and mild alternative to the use of Br2 or other bromine carrying reagents. The substrate scope includes 21 olefins brominated in good to excellent yields. Three of six styrene derivatives yielded bromohydrins in good yields under the reaction conditions.
Chapter 3 discloses the discovery of a synthetic iron-rich nontronite clay and its use as a dehydrogenating reagent. N-heterocycles such as 1,2,3,4-tetrahydrocarbazole, indoline, N-phenylbenzylamine are effectively aromatized by this unique new reagent in refluxing toluene. Extensive reaction optimization, investigation of substrate scope, characterization of the novel heterogeneous reagent is presented.