(4aR,5R,8aS)-1-{(E)-2-[(3R,5R)-3,5-Bis-(tert-butyl-dimethyl-silanyloxy)-cyclohexylidene]-ethylidene}-5-((R)-1,5-dimethyl-5-trimethylsilanyloxy-hex-3-ynyl)-4a-methyl-decahydro-naphthalene