methyl (2S)-2-((2S,5S,6S)-6-{(1R,2R,3R,5S,6R,9E,11R,12R,13E,15R)-2,12-bis[(tert-butyldimethylsilyl)oxy]-6-hydroxy-1,3,5,11,13,15-hexamethyl-4-oxooctadi-9,13-enyl}-5-methyltetrahydro-2H-pyran-2-yl)propanoate