(1R,2R)-1-tert-butyl 2-methyl 4-oxocyclopentane-1,2-dicarboxylate

(1R,2R)-2-(methoxycarbonyl)-4-oxocyclopentanecarboxylic acid

(1R,2R)-1-benzyl 2-methyl 4-oxocyclopentane-1,2-dicarboxylate

(7R,8R)-7-benzyl 8-methyl 1,4-dioxaspiro[4.4]nonane-7,8-dicarboxylate

(7R,8R)-methyl 8-(5-(4-bromophenyl)-1H-imidazol-2-yl)-1,4-dioxaspiro[4.4]nonane-7-carboxylate