(3aR,6aR,7S,8R,8aR,8bR,9aR,11R,11aR,11bR)-11a-hydroxy-2,7,9,9,11-pentamethyl-6a,7,8,8a,8b,9,9a,10,11,11a-decahydro-3H-8,11b-epoxycyclopropa[5',6']benzo[1',2':7,8]azuleno[3a,4-d][1,3]dioxol-5-one