2-((2S,3R,4S,5R,6R)-3-Benzyloxy-6-benzyloxymethyl-5-hydroxy-2-methoxy-tetrahydro-pyran-4-yloxymethyl)-benzoic acid (2S,3R,4S,5R,6R)-4,5-bis-benzyloxy-6-benzyloxymethyl-2-ethylsulfanyl-tetrahydro-pyran-3-yl ester