Regioselective and diastereoselective dimethyldioxirane epoxidation of substituted norbornenes and hexamethyl Dewar benzene

Various substituted norbornenes, such as endo-dicyclopentadiene 1, exo-dicyclopentadiene 5, 5-methylenebicyclo[2.2.1]hept-2-ene 8 and hexamethyl Dewar benzene 10 were transformed into the corresponding mono- and bis-epoxides by epoxidation with dimethyldioxirane (as an acetone solution).