CuBr2-Catalyzed alkenylation of 1-adamantanol with isopropanol

The electrophilic adamantylation of olefins is one of the few synthetic approaches to polycyclic framework compounds with the side chains. The reaction of adamantane with lower olefins on aluminosilicate catalysts leads to alkyladamantanes, and in the case of propylene, a noticeable amount of alkenyladamantanes is formed. In a solution of trifluoromethanesulfonic acid, the reaction of adamantane with olefins gives a mixture of mono- and polysubstituted alkyladamantanes in ~10 % yield. In order to elaborate convenient preparative methods for the selective introduction of a three-carbon fragment into the adamantane framework, we undertook a study of the reaction of 1-adamantanol with isopropanol in the presence of metal-complex catalysts. We have developed for the first time a CuBr₂-catalyzed method for the alkenylation of 1-adamantanol with isopropanol. The reaction proceeds for 4 hours at 220 ^oC giving the corresponding trans-1-adamantylpropene in high yield.