(4E,8E,12E)-(2S,6S,7S,10S,11R)-7,11-Bis-(tert-butyl-dimethyl-silanyloxy)-2,6,8,10,12-pentamethyl-3-oxo-2-trimethylsilanyloxy-tetradeca-4,8,12-trienoic acid benzyl ester

(8E,12E)-(2S,6S,7S,10S,11R)-7,11-Bis-(tert-butyl-dimethyl-silanyloxy)-5-hydroxy-2,6,8,10,12-pentamethyl-3-oxo-2-trimethylsilanyloxy-tetradeca-8,12-dienoic acid benzyl ester