3-[Dimethyl-(1,1,2-trimethyl-propyl)-silanyloxy]-2-[(R)-2-((R)-5-hydroxy-6-trityloxy-hexanoylamino)-2-(3-methyl-[1,2,4]oxadiazol-5-yl)-ethylsulfanylmethyl]-5-methoxy-6-methyl-benzoic acid allyl ester