2-[(cyclopropylmethyl)({[(9H-fluoren-9-yl)methoxy]carbonyl})amino]-2-methylbutanoic acid

3-[2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-4-methylhexanamido]-2-methylbutanoic acid

3-[N-ethyl-2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-4-methylhexanamido]butanoic acid

(2S)-2-[4-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-2-methoxy-N-methylbutanamido]propanoic acid

5-[4-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-2-methoxybutanamido]hexanoic acid

2-{[4-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-2-methoxybutanamido]methyl}-2-methylbutanoic acid

(2R)-2-[4-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-2-methoxybutanamido]-3,3-dimethylbutanoic acid

5-[(3S)-3-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-4-methylpentanamido]pentanoic acid

(2R)-2-[(3S)-3-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-4-methylpentanamido]-3-methylbutanoic acid

(2S,4R)-1-[(3S)-3-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-4-methylpentanoyl]-4-hydroxypyrrolidine-2-carboxylic acid

2-[(3S)-3-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-4-methyl-N-(prop-2-yn-1-yl)pentanamido]acetic acid