(4aR,8R,8aR)-2,2-Di-tert-butyl-6-[(E)-(R)-1-(tert-butyl-dimethyl-silanyloxymethyl)-5-methoxy-pent-3-enyloxy]-8-triisopropylsilanyloxy-hexahydro-1,3,5-trioxa-2-sila-naphthalene-6-carbonitrile