2,2-Dimethyl-propionic acid (10E,16E)-(3R,4R,5R,6R,9S,13R,15R,19S,20R,21S,22S)-5-(tert-butyl-dimethyl-silanyloxy)-9,15-dimethoxy-4,6,13,20,22-pentamethyl-3-methylsulfanylmethoxy-19,21-bis-triethylsilanyloxy-23-trityloxy-tricosa-10,16-dienyl ester