{2-[(2R,3R,4S,5R)-4-Benzyloxy-5-((4S,5S)-2,2-dimethyl-5-trityloxymethyl-[1,3]dioxolan-4-yl)-3-(4-methoxy-benzyloxy)-tetrahydro-furan-2-yl]-ethoxy}-tert-butyl-dimethyl-silane