(2aR,4S,4aS,6S,9S,11S,12S,12aR,12bR)-12-(benzoyloxy)-11-hydroxy-4,6-dimethoxy-4a,8,12b,13,13-pentamethyl-5-oxo-2a,3,4,4a,5,6,9,10,11,12,12a,12b-dodecahydro-1H-7,11-methanocyclodeca[3,4]benzo[1,2-b]oxet-9-yl (4R,5R)-2-(4-methoxyphenyl)-3-nitroso-4-phenyloxazolidine-5-carboxylate