Tricyclo[4.2.2.22,5] dodecane and Tricyclo [4.2.2.12,5]undecane. Preliminary communication

A synthesis of tricyclo 4.2.2.2^2,5]dodecane ( 19 ), a novel tricyclic C₁₂H₂₀ compound, is described. The key intermediate ketone 13 was prepared either from the C₁₀-photodimer 1 of cyclopentadienone or the C₁₁-cycloaddition products 11 and 12 . 13 was also transformed to tricyclo 4.2.2.1^2,5]undecane ( 8 ).