The reaction of [2σ + 2σ + 2π]-cycloaddition of quadricyclane with olefins is an attractive way for regioand sterospecific synthesis of norbornene derivatives (exotricyclononenes) with desired substituents. The presence of Cl 3 Si-containing groups in such compounds permits different monomer modifications for the development of new materials. Herein, for the first time the theoretical and experimental study of the behavior of different ethylenes containing three silyl-groups in the reaction of [2σ + 2σ + 2π]-cycloaddition with quadricyclane was systematically performed. Based on the data obtained for this reaction the activity scale of the ethylene derivatives was established, and the explanations for an ethylene activity were suggested. As a result, a new family of Si-containing tricyclononenes was successfully synthesized. As an example M. Bermeshev ( ) · P. Chapala · M. Filatova · E. Finkelshtein A.V. Topchiev Institute of Petrochemical Synthesis of Russian Academy of Sciences, 29 Leninsky Prospect, of a possible modification, the methylation of the sterically hindered cycloadducts was investigated and the conditions for full methylation were found. Considering that gas permeability of polymers increases with the increase of a number of the side Me 3 Si-groups, the compounds are interesting monomers for synthesis of membrane polymers possessing high gas permeability values.