Sven Andresen and Paul Margaretha
On irradiation (λ=300 nm),2,2,6,6-tetramethylcyclohex-3-enone (1) is cleanly converted into1-(2,2-dimethylcyclopropyl)-2-methylpropene (3); similarly,6-oxo-1,5,5-trimethylcyclohex-2-ene-1-carbonitrile (2) affords amixture of (Z )- and(E )-3-(2,2-dimethylcyclopropyl)-2-methylpropenonitriles4a and 4b.