4,20-Dioxa-3,21-disilatricos-16-en-9-one, 7,11-bis[[(1,1-dimethylethyl)dimethylsilyl]oxy]-2,2,3,3,8,8,12,16,21,21,2 2,22-dodecamethyl-19-(2-methyl-5-benzothiazolyl)-10-(2-propenyl)-, (7S,10R,11S,12