170. J.-L.M. Abboud, I.A. Koppel, I. Alkorta, E.W. Della, P. Müller, J.Z. Dávalos, P. Burk, I. Koppel, V. Pihl, E. Quintanilla,
     “Stereoelectronic, Strain, and Medium Effects on the Protonation of Cubylamine, a Janus-like Base”
     Angew. Chem. Int. Ed. 2003, 42, 2281-2285.

The cubic structure of cubylamine (1NH₂) is maintained on protonation in aqueous solution, but in the gas phase 1NH₂ is irreversibly protonated on the carbon framework, leading to the formation of iminium ions through ring opening.

DOI : 10.1002/anie.200350993