(3S,3aR,4S,6S,6aR,10S,10aR,13aR,16aR,E)-3-benzyl-6-((tert-butyldimethylsilyl)oxy)-4,10,12,12,13a-pentamethyl-5-methylene-15-(phenylselanyl)-3,3a,4,5,6,6a,9,10,10a,13a,14,15-dodecahydro-1H-[1,3]dioxolo[4',5':7,8]cycloundeca[1,2-d]isoindole-1,16(2H)-dione