2-{2-[2-acetoxymethyl-5-acetylamino-6-(bis-benzyloxy-phosphoryloxy)-3-(4,5-diacetoxy-6-acetoxymethyl-3-acetylamino-tetrahydro-pyran-2-yloxy)-tetrahydro-pyran-4-yloxy]-propionylamino}-propionic acid 2-trimethylsilanyl-ethyl ester