(1E,7Z,20Z)-(3R,4S,9S,10R,11S,13S,16R,17R,18S,19S)-4,10,16-Tris-(tert-butyl-dimethyl-silanyloxy)-18-hydroxy-1-iodo-3,9,11,13,17,19-hexamethyl-tricosa-1,7,20,22-tetraen-6-one