Deamination of 2-amino-4,4-dideuterio-6,6-dimethylcyclohexanone, 2-exo-amino- and 2-endo-amino-norbornane-3-one, 2-diazo-norbornan-3-one, 2-exo-amino-5,6-exo-dideuterionorbornan-3-one and the corresponding 5,6-endo-dideuterio isomer has been studied. The nature of the products, the deuterium location in them, and the high retention of steric identity in the carbocations are interpreted in terms of σ-bond participation leading to corner- and edge-protonated cyclopropanes as reaction intermediates. Results with other destabilized carbocations are correlated.