(1R,3S,7S,8E,11S,12S,13E,15S,17R,21R,23S)-17-((R)-1-(benzyloxy)ethyl)-11,21-dihydroxy-13-(2-methoxy-2-oxoethylidene)-10,10-dimethyl-19-oxo-6,18,27,28,29-pentaoxatetracyclo[21.3.1.13,7.111,15]nonacos-8-en-12-yl octanoate