(Z)-Hept-2-en-4-ynoic acid {3-[(1S,11S,13S,15R)-7,15-bis-(tert-butyl-dimethyl-silanyloxy)-9-oxo-10,17-dioxa-tricyclo[11.3.1.03,8]heptadeca-3(8),4,6-trien-11-yl]-1-hydroxy-propyl}-amide