(1R,4S,7R)-2,3-Dihydroxy-1,7-dimethyl-bicyclo[2.2.1]heptane-7-carboxylic acid benzyl ester

(1R,4S,7R)-1,7-Dimethyl-2,3-dioxo-bicyclo[2.2.1]heptane-7-carboxylic acid benzyl ester

(1R,2R,5S)-2,5-Bis-hydroxymethyl-1,2-dimethyl-cyclopentanecarboxylic acid benzyl ester