(2aE,4E,8E)-20,20b-dihydroxy-5',6,8,19-tetramethyl-6'-(1-methylpropyl)-17-oxo-5',6,6',10,11,14,15,17,17a,20,20a,20b-dodecahydro-2H,7H-spiro[11,15-methanofuro[4,3,2-pq][2,6]benzodioxacyclooctadecine-13,2'-pyran]-7-yl 2,6-dideoxy-4-O-(2,6-dideoxyhexopyranos