Date of Award
Doctor of Philosophy
Richard C. Larock
This dissertation is divided into two sections. The research in each section is of an entirely different nature. The focus of the first section will be different approaches to asymmetric organic photochemistry. The focus of the second section will be palladium-catalyzed allylic arylation of cyclic alkenes;The first section will discuss three different sets of experiments, aimed at exploring different aspects of asymmetric organic photochemistry. A model system involving the concept of chiral electron-transfer sensitizers is explored first. The latter two studies involve photochemically-induced [pi] bond rotation in allenes. The photoracemization of optically active 1,3-diphenylallene is observed and the quantum yield for this process is determined. Then the same substrate, as a racemic modification, is partially resolved using circularly-polarized light. Thus, both the photoracemization and the photoresolution of 1,3-diphenylallene are performed;The second section will discuss the development and study of a general synthetic method for the allylic arylation of cyclic alkenes. The section is composed of two parts, the first dealing with intermolecular arylation and the second dealing with intramolecular arylation using this new synthetic method. Although this synthetic transformation has been examined by other chemists, our approach is unique in that reactions proceed at lower temperatures, require only catalytic amounts of a palladium salt, use more stable, readily-available starting materials, proceed in good to excellent yields, and provide a single product free of isomeric mixtures which have traditionally been obtained from previous palladium-catalyzed arylation reactions. Intermolecular arylation has been conducted using cycloalkene rings of five to eight members, and a wide variety of aromatic and some heteroaromatic halides. Intramolecular cycloalkene arylations have been used to synthesize both carbocycles and heterocycles. The formation of both five and six membered rings will be shown to occur in good yields, and cyclization onto cycloalkenes of five to seven members will be demonstrated.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Bruce Edward Baker
Baker, Bruce Edward, "I. Asymmetric organic photochemistry; II. Palladium-catalyzed allylic arylation of cyclic alkenes " (1988). Retrospective Theses and Dissertations. 8823.