(1S,2S,4aS,4bR,9R,10aS)-9-<(tert-Butyldimethylsilyl)oxy>-1,2,3,4,4a,4b,5,6,7,9,10,10a-dodecahydro-2-(methanesulfonyl)-1,4a-dimethylphenanthren-7-one