[(2R,3S,5R,6S)-5-Benzyloxy-6-(2-benzyloxy-ethyl)-2-((2R,4aR,9aS)-2-phenyl-4a,8,9,9a-tetrahydro-4H-1,3,5-trioxa-benzocyclohepten-6-ylmethyl)-tetrahydro-pyran-3-yloxy]-tert-butyl-dimethyl-silane