The synthesis of the eudesmanolide torrentin (1) by sensitized photooxygenation of synthetic dihydrosantamarine (3) is reported. Both dihydrosantamarine and dihydroreynosin (11) were obtained from the 1,2-epoxide 9, which, in turn, was prepared from the diselenide 7. An improved procedure for the synthesis of the elemanolide saussurea lactone (4) is also reported. Keywords: eudesmanolide, elemanolide, santonin, torrentin, saussurea lactone.