(R)-[(3aR,5S,6R,6aR)-6-(tert-Butyl-dimethyl-silanyloxymethyl)-6-methoxycarbonylmethyl-2,2-dimethyl-tetrahydro-furo[2,3-d][1,3]dioxol-5-yl]-methoxy-acetic acid methyl ester

(3aR,4aS,5R,7aR,7bR)-7a-Acetoxymethyl-6-(2,2-dimethyl-propionyloxy)-5-methoxy-2,2-dimethyl-4a,5,7a,7b-tetrahydro-3aH-cyclopenta[4,5]furo[2,3-d][1,3]dioxole-7-carboxylic acid methyl ester

(3R,4S,5R)-5-Acetoxymethyl-5-(bis-ethylsulfanyl-methyl)-2-(2,2-dimethyl-propionyloxy)-4-hydroxy-3-methoxy-cyclopent-1-enecarboxylic acid methyl ester

(3aR,4aS,5S,8aR,8bR)-5-(tert-Butyl-diphenyl-silanyloxymethyl)-2,2-dimethyl-8a-vinyl-hexahydro-[1,3]dioxolo[4,5]furo[2,3-c]pyran-7-one

{(3aR,5S,6R,6aR)-5-[(R)-2-(tert-Butyl-diphenyl-silanyloxy)-1-methanesulfonyloxy-ethyl]-2,2-dimethyl-6-vinyl-tetrahydro-furo[2,3-d][1,3]dioxol-6-yl}-acetic acid ethyl ester