(2R,3S)-4-Acetyl-1-[4-(5-fluoro-2-methyl-benzyloxy)-benzenesulfonyl]-3-methyl-piperazine-2-carboxylic acid tert-butyl ester

(2R,3R)-1-[4-(2-Ethyl-benzyloxy)-benzenesulfonyl]-3-methyl-aziridine-2-carboxylic acid tert-butyl ester

(2R,3S)-3-(2-Hydroxy-ethylamino)-2-[4-(2-trifluoromethyl-benzyloxy)-benzenesulfonylamino]-butyric acid tert-butyl ester

(2R,3S)-4-Acetyl-3-methyl-1-[4-(2-trifluoromethyl-benzyloxy)-benzenesulfonyl]-piperazine-2-carboxylic acid tert-butyl ester

(2S,3R)-tert-Butyl 2-hydroxy-3-(N-benzyloxycarbonyl-N-methyl)aminobutanoate