(R)-6-[(1E,3Z,7E,9E)-(5R,11R,12S,13R,14R,15S)-14-(tert-Butyl-dimethyl-silanyloxy)-12-hydroxy-5,9,11,13,15-pentamethyl-heptadeca-1,3,7,9-tetraenyl]-5,6-dihydro-pyran-2-one