(R)-5-{(S)-6-[(1S,2R)-1,2-Dimethyl-6-oxo-2-(2-oxo-ethyl)-cyclohexyl]-2-methyl-4-oxo-hexyl}-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester

(R)-5-{(S)-6-[(1S,2R)-2-(2-Hydroxy-ethyl)-1,2-dimethyl-6-oxo-cyclohexyl]-2-methyl-4-oxo-hexyl}-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester

(R)-5-[(S)-6-((1S,2R)-2-Carboxymethyl-1,2-dimethyl-6-oxo-cyclohexyl)-2-methyl-4-oxo-hexyl]-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester