1-{(4S,6S)-6-[2-(p-methoxybenzyloxy)ethyl]-2,2-dimethyl[1,3]dioxan-4-yl}-3-[2-[(2S,5R)-5-methyl-4-methylene-2,6-bis(triethylsilanyloxy)hexyl][1,3]dithian-2-yl]propan-2-one