(S)-5-{(2R,3R,4S)-3-(benzyloxy)-4-[(4S,5S)-2,2,5-trimethyl-1,3-dioxan-4-yl]pentan-2-yl}-2,2,3,3,10,10-hexamethyl-9,9-diphenyl-4,8-dioxa-3,9-disilaundecane