3-{[((3S,10S,30S,2R,12R,19R,27R)-30-Hydroxy-27-methoxy-2,3,17,19-tetramethyl-9,13,25-trioxa-8-oxospiro[2H-3,4,5,6-tetrahydropyran-6,6'-tetracyclo[15.6.1.1<4,8