(1S,2S,13S)-2,13-Bis-(tert-butyl-dimethyl-silanyloxy)-1-hydroxy-12,15,15-trimethyl-tricyclo[9.3.1.03,8]pentadeca-3,5,7,11-tetraen-9-one

(1S,2S,13S)-2,13-Bis-(tert-butyl-dimethyl-silanyloxy)-1-hydroxy-12,15,15-trimethyl-tricyclo[9.3.1.03,8]pentadeca-3,7,11-trien-9-one