FUNCTIONALIZATION OF MONO- AND DIPYRROLIC COMPOUNDS

Abstract

Chemical manipulations of pyrrolic compounds can often prove to be difficult. This is especially true for dipyrrins. As a result of this, methodology development for the chemical manipulation of pyrrolic compounds is of particular interest. The graduate work presented herein involves three projects dedicated to developing such methodologies. Based on microwave-promoted deprotection of F-BODIPYs previously developed by the Thompson group, an F-BODIPY was probed for use as a protecting group option for the manipulation of the parent dipyrrin. Rather than isolating the expected functional group interconversion product, the F-BODIPY was deprotected and the resulting dipyrrin was reduced to form its corresponding dipyrromethane in moderate yield. A series of reactions using similar conditions and substrates were performed to explore the scope of this reaction. Methodologies for the manipulation of functional groups can also prove useful when trying to improve the stability of a molecule. Porphomethenes suffer from auto-oxidation due to the inherent stability of their oxidized counterparts, porphyrins. Oxidation of the susceptible bridgehead carbon atoms may be prevented via an isosteric replacement (by replacing C-H with C-F). However, while developing model meso-difluorodipyrromethane systems for study, complications arose due to the interesting electronic properties of pyrrole. These complications were studied instead, in the hopes of eventually correcting the methodology. In addition, the choice of substitution on a pyrrole can affect the success or failure of a reaction. While attempting to expand upon a known series of bis(ruthenium-pyrrolyl) complexes, ligand synthesis proved to be more challenging than anticipated as a result of choice in substitution on the pyrrolic moiety. Again, a study of these complications was pursued with the intention of developing a successful methodology. As a whole, this thesis portrays some of the trials and tribulations often involved when working towards the successful chemical manipulation of pyrrolic compounds. It is with the hope of the author to both educate on some of the intricacies involved when handling pyrrolic compounds, and inspire others to aid in the quest towards easier and more reliable ways to chemically manipulate pyrroles.