Acetic acid (R)-2-[(1R,2S)-2-(tert-butyl-diphenyl-silanyloxymethyl)-1-methyl-5-oxo-cyclopentyl]-1-[(3aS,5aR,6S,9aS,9bR)-2,2-dimethyl-5,8-dioxo-5a-(2-trimethylsilanyl-ethoxymethoxymethyl)-decahydro-naphtho[1,2-d][1,3]dioxol-6-yl]-ethyl ester

((4S,5R)-2,2-Dimethyl-5-vinyl-[1,3]dioxolan-4-yl)-acetaldehyde