5-O-[(1S,2S,3R,4S,7R,9S,10S,12R,15S)-4-acetyloxy-2-benzoyloxy-1-hydroxy-9,12-dimethoxy-10,14,17,17-tetramethyl-11-oxo-6-oxatetracyclo[11.3.1.03,10.04,7]heptadec-13-en-15-yl] 3-O-tert-butyl (4R,5R)-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-3,5-dicarboxylate