(E)-(S)-5-[(2R,3S,4aR,5aS,8R,9S,10aR,11R,12aS)-9-((2R,3R)-3-Hydroxymethyl-3-methyl-oxiranylmethyl)-3,8,11-trimethyl-3,8-bis-trimethylsilanyloxy-dodecahydro-1,5,10-trioxa-benzo[b]heptalen-2-yl]-pent-3-en-2-ol