The Formation of 1,2-Dioxolanes: I. By the Acid-Catalyzed Addition of H2O2 to ss,gamma-Epoxy Ketones II. By the Chromium-Catalyzed Allylic Peroxidation of a Triterpene Using O2 III. By the Metal-Catalyzed Addition of O2 to Substituted ss-Keto Esters Via a

Peroxide-containing small molecules are therapeutically valuable agents but are difficult to synthesize in high yields due to their weak peroxide bond. This dissertation presents two high-yielding methods to form five-membered ring endoperoxides and discusses progress made towards peroxidizing ss-keto esters. Chapter One provides insight into the mechanism of the acid-catalyzed addition of H2O2 to ss,gamma-epoxy ketones, which guided the optimization of the reaction to favor the formation of 1,2-dioxolanes in moderate to high yields. Studies of the reactivity of 1,2-dioxolanes, affording anticancer natural product analogues, are also included in Chapter One. Chapter Two describes investigations of an anticancer triterpene upon treatment of O2 with a catalytic amount of a chromium complex to provide a 1,2-dioxolane efficiently. A mechanism, which involves allylic, alpha-acyl, and persistent peroxyl radicals, was proposed to account for the required functional groups in this transformation. The participation of these radicals in the oxidation motivated the method described in Chapter Three. The Chapter shows that the addition of a metal-generated peroxyl radical to an alpha-acyl radical of a substituted ss-keto ester formed unexpected oxidation products, such as oxetanes.