1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl 2,4-dioxo-1,3-diazaspiro[4.5]decane-8-carboxylate

(3R)-3-[(3S)-3-[({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)methyl]-5-methylhexanamido]butanoic acid

(3R)-3-(2-{[2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)ethyl]sulfanyl}acetamido)butanoic acid

rac-1-[(2R,3R)-3-[({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)methyl]oxolane-2-carbonyl]azetidine-2-carboxylic acid

2-[3-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)pentanamido]-3-(1,3-thiazol-5-yl)propanoic acid

3-({4-[({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)methyl]-1-methyl-1H-pyrazol-5-yl}formamido)-2-hydroxypropanoic acid

2-(1-{2-[3-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)cyclobutyl]acetyl}azetidin-3-yl)propanoic acid

3-[2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)pent-4-ynoyl]-3-azabicyclo[3.1.0]hexane-1-carboxylic acid

8-[3-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-2-methylpropanoyl]-8-azabicyclo[3.2.1]octane-3-carboxylic acid

2-[4-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-3-hydroxybutanoyl]-2-azabicyclo[2.1.1]hexane-5-carboxylic acid

(2S,3R)-3-(benzyloxy)-2-[7-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)heptanamido]butanoic acid