2,2-Dimethyl-propionic acid (2R,3R)-3-(tert-butyl-dimethyl-silanyloxy)-3-{(4S,5S)-5-[(E)-(S)-3-(1,4-dioxa-spiro[4.4]non-2-yl)-buta-1,3-dienyl]-2,2-dimethyl-[1,3]dioxolan-4-yl}-2-methyl-propyl ester

(2R,3R)-3-{(4S,5S)-5-[(E)-(S)-4,5-Bis-(tert-butyl-dimethyl-silanyloxy)-3-methylene-pent-1-enyl]-2-methoxy-[1,3]dioxolan-4-yl}-3-(tert-butyl-dimethyl-silanyloxy)-2-methyl-propan-1-ol

2,2-Dimethyl-propionic acid (2R,3R)-3-[(4S,5S)-5-((S)-2-acetoxy-3-1,4-dioxa-spiro[4.4]non-2-yl-but-3-enyl)-2,2-dimethyl-[1,3]dioxolan-4-yl]-3-(tert-butyl-dimethyl-silanyloxy)-2-methyl-propyl ester

(4S,5S)-4-[(E)-(R)-4,5-Bis-(tert-butyl-dimethyl-silanyloxy)-3-methylene-pent-1-enyl]-5-[(1R,2S)-1-(tert-butyl-dimethyl-silanyloxy)-3-iodo-2-methyl-propyl]-2-methoxy-[1,3]dioxolane

(4S,5S)-4-[(E)-(S)-4,5-Bis-(tert-butyl-dimethyl-silanyloxy)-3-methylene-pent-1-enyl]-5-[(1R,2S)-1-(tert-butyl-dimethyl-silanyloxy)-3-iodo-2-methyl-propyl]-2-methoxy-[1,3]dioxolane