(2S,4S)-2-amino-5,5,5-trifluoro-4-methylpentanoic acid hydrochloride

(2S,4S)-2-amino-5-azido-4-fluoropentanoic acid hydrochloride

(2S,4S)-2-amino-5-carbamimidamido-4-fluoropentanoic acid dihydrochloride

(2S,4S)-2-amino-5-fluoro-4-methylpentanoic acid hydrochloride

(2s,4s)-2-amino-5-oxa-7-azaspiro[3.4]octan-6-one hydrochloride

(2s,4s)-2-amino-5-oxaspiro[3.4]octan-7-ol hydrochloride

(2S,4S)-2-cyclobutyl-3,4-dihydro-2H-1-benzopyran-4-ol

(2S,4S)-2-cyclopentyl-3,4-dihydro-2H-1-benzopyran-4-ol

(2s,4s)-2-hydroxy-5-oxa-7-azaspiro[3.4]octan-6-one

(2s,4s)-2-methoxy-2-(trifluoromethyl)-8-oxa-5-azaspiro[3.5]nonane hydrochloride

(2S,4S)-2-methyl-3,4-dihydro-2H-1-benzopyran-4-amine hydrochloride

(2S,4S)-2-methyl-3,4-dihydro-2H-1-benzopyran-4-ol

(2s,4s)-2-methyl-5-oxaspiro[3.4]octane-2-carboxylic acid

(2S,4S)-2-tert-butyl-6-fluoro-3,4-dihydro-2H-1-benzopyran-4-amine

(2S,4S)-2-{[(tert-butoxy)carbonyl]amino}-4-carbamoyl-4-fluorobutanoic acid

(2S,4S)-4-(1H-1,2,3-triazol-1-yl)pyrrolidine-2-carboxylic acid dihydrochloride

(2S,4S)-4-(benzyloxy)pentan-2-ol

(2S,4S)-4-(difluoromethoxy)-1-{[(9H-fluoren-9-yl)methoxy]carbonyl}pyrrolidine-2-carboxylic acid

(2S,4S)-4-(ethylamino)-2-methyl-1,1-dioxo-2H,3H,4H-1lambda6-thieno[2,3-b]thiopyran-6-sulfonamide hydrochloride

(2S,4S)-4-(pyridin-4-yloxy)pyrrolidine-2-carboxylic acid dihydrochloride

(2S,4S)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid hydrochloride

(2S,4S)-4-amino-1-[(tert-butoxy)carbonyl]pyrrolidine-2-carboxylic acid

(2S,4S)-4-amino-2-methyl-2H,3H,4H-1lambda6-thieno[2,3-b]thiopyran-1,1-dione

(2S,4S)-4-azido-1-[(tert-butoxy)carbonyl]pyrrolidine-2-carboxylic acid

(2S,4S)-4-azido-1-{[(9H-fluoren-9-yl)methoxy]carbonyl}pyrrolidine-2-carboxylic acid

(2S,4S)-4-azido-2-methyl-2H,3H,4H-1lambda6-thieno[2,3-b]thiopyran-1,1-dione

(2S,4S)-4-azidopyrrolidine-2-carboxylic acid; trifluoroacetic acid

(2S,4S)-4-carbamoyl-2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-4-fluorobutanoic acid

(2S,4S)-4-chloro-1-{[(9H-fluoren-9-yl)methoxy]carbonyl}pyrrolidine-2-carboxylic acid

(2S,4S)-4-cyclohexyl-1-methylpyrrolidine-2-carboxylic acid

(2S,4S)-4-cyclohexyl-1-{[(9H-fluoren-9-yl)methoxy]carbonyl}pyrrolidine-2-carboxylic acid

(2S,4S)-4-cyclohexyl-2-(trifluoromethyl)pyrrolidine

(2S,4S)-4-cyclohexyl-N-methylpyrrolidine-2-carboxamide hydrochloride

(2S,4S)-4-cyclohexylpyrrolidine-2-carboxylic acid

(2S,4S)-4-fluoro-1-methyl-5-oxopyrrolidine-2-carboxylic acid

(2S,4S)-4-fluoro-1-methylpyrrolidine-2-carboxylic acid hydrochloride

(2S,4S)-4-fluoro-2-(methanesulfonylmethyl)pyrrolidine hydrochloride

(2S,4S)-4-fluoro-2-(trifluoromethyl)pyrrolidine hydrochloride

(2S,4S)-4-fluoro-5-oxopyrrolidine-2-carboxamide

(2S,4S)-4-fluoro-5-oxopyrrolidine-2-carboxylic acid

(2S,4S)-4-fluoropyrrolidine-2-carboxylic acid hydrochloride

(2S,4S)-4-hydroxy-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid hydrochloride

(2S,4S)-4-hydroxy-N,N-dimethylpyrrolidine-2-carboxamide hydrochloride

(2S,4S)-4-hydroxypyrrolidine-2-carboxylic acid

(2S,4S)-4-hydroxypyrrolidine-2-carboxylic acid hydrochloride