(S)-2-[(7R,8S,9R)-9-((1R,3R)-3-{(4R,5S,6R)-6-[(S)-2-(tert-Butyl-diphenyl-silanyloxy)-1-methyl-ethyl]-2,2,5-trimethyl-[1,3]dioxan-4-yl}-3-hydroxy-1-methyl-butyl)-8-methyl-6,10-dioxa-spiro[4.5]dec-7-yl]-2-hydroxy-pentan-3-one