Beh, MichaelFigliola, CarlottaLund, Kate-Lyn A. R.Kajetanowicz, Aleksandra K.Johnsen, Ann E.Aronitz, Elise M.Thompson, Alison2018-11-142018-11-142018Regioselective Substituent Effects upon the Synthesis of Dipyrrins from 2-Formyl Pyrroles. Beh, M.H.R.; Figliola, C.; Lund, K-l. A.R.; Kajetanowicz, A.K.; Johnsen, A.E.; Aronitz, E.M.; Thompson, A. Can. J. Chem. 2018, 96, 779-784, special issue to honour Dalhousie’s 200th anniversary (NSERC). https://doi.org/10.1139/cjc-2017-0662http://hdl.handle.net/10222/74957Post-printThe synthesis of symmetric α-free meso-H-dipyrrin hydrobromides from 5-H-2-formyl pyrroles was investigated. The self-condensation produces regioisomeric dipyrrins through the adoption of two mechanistic pathways. The key difference between the two pathways lies in which position of the pyrrole directs nucleophilic attack. Through a systematic study involving various substituted and/or isotopically labelled 5-H-2-formyl pyrroles, we herein provide evidence to suggest that not only do two mechanistic pathways exist but that the steric bulk of the substituent adjacent to the 5-unsubstituted position influences which pathway dominates.Article