X-ray Crystallographic and 13C NMR Investigations of the Effects of Electron Withdrawing Groups on a Series of Pyrroles
Thompson, A., Gao, S., Modzeleweska, G., Hughes, D.S., Patrick, B., and David Dolphin
A series of pyrroles substituted with various electron-withdrawing groups (EWGs) on the N atom have been synthesized and full characterization including X-ray crystal structures obtained. Analysis of 13C chemical shifts and X-ray crystal structures reveals that a trend between decreased aromaticity and the strength of the EWG exists. Experimental results regarding alternative mechanisms of nucleophilic substitution reactions can thus be rationalized.