(E)-3-{(2R,3R)-3-[(2R,4aR,6S,7R,8aS)-7-(tert-Butyl-dimethyl-silanyloxy)-6-methyl-2-phenyl-hexahydro-pyrano[3,2-d][1,3]dioxin-6-ylmethyl]-oxiranyl}-2-methyl-acrylic acid ethyl ester