(1S,2S,3R,4S,7R,9S,10R,12R,15S)-4-acetoxy-2-(benzoyloxy)-1-hydroxy-9,12-dimethoxy-10,14,17,17-tetramethyl-6-oxatetracyclo[11.3.1.03,10.04,7]heptadec-13(14)-en-15-yl (4R,5R)-2-(4-methoxyphenyl)-3-{[(2-methylprop-2-yl)oxy]carbonyl}-4-phenyl-1,3-oxazolidine-5-carboxylate