(2S,7aR,8R,10R,11R,13S,13aS,13bR)-11-(1-hydroxy-1-methylethyl)-1,1,7a,8,13a-pentamethyloctadecahydro-10,12a-epoxycyclopropa[1',8a']naphtho[2',1':4,5]indeno[2,1-b]oxepine-2,13-diol