(3S,5S)-3,5-Dihydroxy-7-[(1S,2S,4aR,8S,8aS)-2-methyl-8-((S)-2-methyl-butyryloxy)-1,2,4a,5,6,7,8,8a-octahydro-naphthalen-1-yl]-heptanoic acid methyl ester