Acetic acid (3aR,4S,6S,7R,7aR)-3-(tert-butyl-dimethyl-silanyl)-7-methoxy-4,7a-dimethyl-2-oxo-hexahydro-pyrano[3,4-d]oxazol-6-yl ester

3-(tert-butyl-dimethyl-silanyl)-6-{5-[6-(2-chloro-cyclopropyl)-hexa-1,3-dien-5-ynyl]-1-hydroxy-9-methoxy-7,10,12-trimethyl-3-oxo-4,15-dioxa-bicyclo[9.3.1]pentadec-7-en-13-yloxy}-7-methoxy-4,7a-dimethyl-tetrahydro-pyrano[3,4-d]oxazol-2-one