(1R)-3endo-hydroxy-4,7,7-trimethyl-norbornane-2exo-carboxylic acid

1,7,7-trimethylbicyclo(2.2.1)hept-2-ene-2-carboxylic acid

2-bromomethyl-1,2-dimethyl-cyclopentane-1,3-dicarboxylic acid

(1S,3R)-3-carbamoyl-2,2,3-trimethylcyclopentane-1-carboxylic acid

(1R,3S)-3-aminocarbonyl-1,2,2-trimethylcyclopentane-1-carboxylic acid