{(1′R,2S,3R,4′S,5S,6S,8′R,10′E,13′R,14′E,16′E,21′R,24′S)-6-[(2E)-2-Buten-2-yl]-3,21′,24′-trihydroxy-5,11′,13′-trimethyl-2′-oxo-3,4,5,6-tetrahydrospiro[pyran-2,6′-[3,7,19]trioxatetracyclo[15.6.1.1~4,8~ .0~20,24~]pentacosa[10,14,16,22]tetraen]-22′-yl}methyl 3-methylbutanoate