Under thermal conditions, tritylimidazoles have been shown to undergo sterically driven N-->N trityl migrations, in disagreement with previously published reports. These migrations are a key step in several highly diastereoselective domino reaction sequences (Diels-Alder, [1,3]-H shift, [1,3]-trityl migration and Diels-Alder, [1,3]-H shift, [1,3]-trityl migration, Michael reaction) leading to architecturally complex molecules.