Department of Chemistry
Master of Science
Site-specific product(s) from the reaction of benzene derivatives with various reagents is a need of researchers at numerous laboratories, particularly those in the pharmaceutical industry. Such derivatives can be synthesized directly, i.e., by substitution of a proton, using either of two procedures: electrophilic aromatic substitution (EAS) or directed ortho-metalation (DoM). Directed ortho-metalation (DoM) is an alternative aromatic substitution process initiated by organolithium reagents which provides regiospecific substitution exclusively at the ortho- position (equation). The focus of this study is to find hydrocarbon media that will permit the maximum extent of metalation of several dimethylarylamines. The dimethylamine-containing substituents constitute directing metalation groups (DMG's) for the various aryl systems investigated. Maximization of the extents of ortho-lithiation of dimethylaniline [DMG = - N(CH3)2] and dimethylbenzylamine [DMG = -CH2N(CH3)2] have now been achieved using novel combinations of solvent, temperature and increments of catalyst. Studies of substituted dimethylanilines and dimethylbenzylamines containing a second DMG have yielded mixed results. Both metalation condition parameters as well as certain mechanistic aspects are altered by inclusion of a second DMG into these two parent systems.
Timmons, Michael, "Directed Ortho-Metalation of Dimethylarylamines" (2002). Masters Theses & Specialist Projects. Paper 641.