(S)-3-(tert-Butyl-dimethyl-silanyloxy)-pentanedioic acid mono-[(S)-3-(2-chloro-acetoxy)-1-((2S,6S,7S,10R)-7-isopropyl-10-methyl-1,5-dioxa-spiro[5.5]undec-2-ylmethyl)-2,2-dimethyl-propyl] ester

octanoic acid 19-(1-benzyloxy-ethyl)-11-(2-chloroacetoxy-1,1-dimethyl-ethyl)-1,15-dihydroxy-23-methoxycarbonylmethylene-2,2-dimethyl-13,17-dioxo-6,12,18,25,26-pentaoxa-tricyclo[19.3.1.15,9]hexacos-3-en-24-yl ester