The possibility of using the transition state shape selectivity concept for control of selectivity of reaction was previously demonstrated by us using the example of 1,3-dioxanes formation by Prins reaction. The extension of the applied approach to other reactions is of theoretical and practical interest. Considering that the main channel for the formation of 1,3-dioxanes by Prins reaction is realized through a cyclic transition state, it is primarily interesting to study the applicability of the above approach to other reactions also proceeding through a cyclic transition state: Claisen rearrangement, Diels-Alder reaction, etc. The aim of our work was to study the interaction of the frozen transition state of Claisen rearrangement with the surface of nanotubes of various structures to predict their catalytic activity. Claisen rearrangement of allylphenyl ether was chosen as a model reaction, and carbon nanotubes with different diameters were chosen as a porous materials. The calculated dependence of the stabilization energy on the nanotube diameter has an extreme character with pronounced maxima at a diameter of 10.2–10.4 Å. The obtained results allow to predict the catalytic activity of nanotubes with a diameter of 10-11 Å in Claisen rearrangement of allylphenyl ether.