Abstract The ring opening of 3-aza 1, 8, 8-trimethyl tricyclo [5.2. 1.0 2, 4] octane isomers by HF-pyridine has been studied. A series of γ-fluoroamines and non fluorinated amines, isomers of the starting aziridines, was obtained. No β-fluoroamines were isolated. The structures of diastereoisomeric amines, established by 1 H and 19 F NMR, show product structure dependence upon the exo-endo aziridine configuration. A comparison between ...