A Look into the Reactivity and Functionality of Pyrroles and Dipyrrins

Abstract

The dipyrrin unit formally consists of a pyrrolic unit and an aza-fulvenium unit. Within this thesis, two projects involving pyrroles and dipyrrins will be discussed. 2-Formyl pyrroles play a critical role in pyrrole chemistry because they act as a precursor to multi-pyrrolic compounds including dipyrrins. Herein a new synthetic route to 2-formyl pyrroles from 2-thionoester pyrroles is explored. 2-Thionoester pyrroles, when treated with Raney nickel in acetone, are reduced to their corresponding 2-formyl pyrroles. Along with the optimization process of this desulfurative reduction, mechanistic studies are discussed. By arylating the α-, β-, and meso-positions of dipyrrins, we wish to establish a synthetic pathway for each position of arylation. Through pre-functionalization of pyrroles and Suzuki coupling, α-Ph and β-Ph dipyrrins were synthesized. Miyaura borylation of dipyrrins were attempted to explore a new synthetic route to introduce an aryl moiety onto the dipyrrin core.