1,4:5,8:9,12-Trimethanotriphenylene,2,6,10-tris[[(1,1-dimethylethyl)dimethylsilyl]oxy]-1,2,3,4,5,6,7,8,9,10,11,12-dodecahydro-, (1S,2R,4S,5S,6R,8S,9S,10R,12S)-