The dimerization and photochemical rearrangement of pentacyclo-[5.4.0.02,6.03,10.05,9]undecane-8-thione

Pentacyclo[5.4.0.02,6.03,10.05,9]undecan-8-one 1 is readily sulfurated into pentacyclo[5.4.0.02,6.03,10.05,9]undecane-8-thione 2 with Lawesson’s reagent in dry THF. Upon standing at ambient temperature the thione 2 formed the corresponding thio-dimer 3 within 10 days. When the thio-dimer 3 was exposed to oxygen and ultraviolet light an unexpected photochemical oxidation and rearrangement took place to form the stable disulfenate 5.