tert-butyl-substituted tripyrranes: Insights into the steric and conformational factors that influence porphyrinoid ring formation in the "3 + 1" methodology
The MacDonald "3 + 1" route for porphyrinoid synthesis involves the acid-catalyzed condensation of tripyrranes with monocyclic dialdehydes, followed by an oxidation step. In the present study, yields were found to be greatly diminished when tert-butyl sub