{(S)-1-[(1R,2S,5S)-2-(2-Carbamoyl-1-cyclobutylmethyl-2-oxo-ethylcarbamoyl)-6,6-dimethyl-3-aza-bicyclo[3.1.0]hexane-3-carbonyl]-2,2-dimethyl-propyl}-carbamic acid tert-butyl ester

{(S)-2-[(1R,2S,5S)-2-(2-Carbamoyl-1-cyclobutylmethyl-2-hydroxy-ethylcarbamoyl)-6,6-dimethyl-3-aza-bicyclo[3.1.0]hex-3-yl]-1-cyclohexyl-2-oxo-ethyl}-carbamic acid tert-butyl ester

(1R,2S,5S)-(6,6-dimethyl-3-azabicyclo[3.1.0]hex-2-yl)methanol

(1R,2S,5S)-3-(2,2-Dimethyl-propionyl)-6,6-dimethyl-3-aza-bicyclo[3.1.0]hexane-2-carboxylic acid

(1R,2S,5S)-3-(2,2-Dimethyl-propionyl)-6,6-dimethyl-3-aza-bicyclo[3.1.0]hexane-2-carboxylic acid benzyl ester