(1R,2'R,3'S,4S,6'S,8R,10E,12S,13S,14E,16E,20R,21R,24S)-12-{[(2R,4S,5S,6S)-5-{[(2S,4S,5S,6S)-5-hydroxy-4-methoxy-6-methyl-3,4,5,6-tetrahydro-2H-pyran-2-yl]oxy}-4-methoxy-6-methyl-3,4,5,6-tetrahydro-2H-pyran-2-yl]oxy}-2'-[(2S)-but-2-yl]-21,24-dihydroxy-3',11,13,22-tetramethyl-2',3'-dihydrospiro[3,7,19-trioxatetracyclo[18.3.1.14,8.017,24]pentacosa-10,14,16,22-tetraene-6,6'-pyran]-2-one