(2S,4R)-4-Acetoxy-2-tert-butylcarbamoyl-piperidine-1-carboxylic acid tert-butyl ester

(S)-2-((R)-1,2-Bis-benzyloxy-ethyl)-1-((R)-1-phenyl-ethyl)-piperidin-4-one

(2S,4R)-4-Acetoxy-2-((R)-1,2-bis-benzyloxy-ethyl)-piperidine-1-carboxylic acid tert-butyl ester

Acetic acid (2S,4R)-2-((R)-1,2-bis-benzyloxy-ethyl)-1-((R)-1-phenyl-ethyl)-piperidin-4-yl ester

(5S)-tert-butoxycarbonylamino-5-tert-butylcarbamoyl-3-oxopentanoic acid benzyl ester