(2E,4E,14E,20E)-(7R,8R,9R,10R,13S,17R,19R,23S,24R,25S,26S)-9-(tert-Butyl-dimethyl-silanyloxy)-13,19-dimethoxy-8,10,17,24,26-pentamethyl-7-methylsulfanylmethoxy-23,25-bis-triethylsilanyloxy-27-trityloxy-heptacosa-2,4,14,20-tetraenoic acid ethyl ester