Reactions of exo-exo-hexacyclo[9.2.1.0^2,10.0^3,8.0^4,6.0^5,9]tetradecane with aliphatic alcohols under the action of ionic liquids

Despite the existence of a wide range of known catalysts, chemical engineering and organic synthesis is constantly in need of new, more efficient and environmentally acceptable catalysts and reaction media. Ionic liquids (ILs) meet these requirements. For example, ILs based on aluminum, iron, and other metal halides are an alternative to traditional catalysts, in particular, they catalyze Friedel-Crafts alkylation and acylation reactions, hydrogenation, and isomerization of alkanes and polycyclic hydrocarbons.

On the other hand, the chemistry of small cycles is an intensively developing branch of organic chemistry. Three-carbon rings are unique fragments that, due to their significant stress, are capable of unusual structural transformations with expansion and rearrangement of the small ring.

The reactions of cyclopropane compounds have been actively studied for more than three decades. In the world literature, there are very few examples of works on the functionalization of highly stressed cyclopropane-containing polycyclic hydrocarbons, the reaction products of which can be widely used as precursors for the synthesis of drugs, depressant additives to rocket fuels, and also as transmission media and working fluids. In addition, the analysis of literature data showed that ring-opening reactions of cyclopropanes are catalyzed mainly by transition metal complexes and there are no examples of the use of ILs as catalysts or their transformations.

In this work, we have developed new methods for the synthesis of previously undescribed 4-exo-alcoxypentacyclo[8.2.1.1^5,8.0^2,9.0^3.7]tetradecanes by the reaction of a saturated dimer of norbornadiene - exo-exo-hexacyclo[9.2.1.0^2,10.0^3,8.0^4,6.0^5.9]tetradecane with aliphatic alcohols C₁-C₄ under the action of ILs.