Boc-D-5-hydroxyproline ethyl ester

2-tert-butyl 3-ethyl (1S,3R,5S)-2-azabicyclo[3.1.0]hexane-2,3-dicarboxylate

(R)-2-(adamantan-1-yl)-2-((tert-butoxycarbonyl)amino)acetic acid

1-tert-butyl 2-ethyl (2R)-2,3-dihydro-1H-pyrrole-1,2-dicarboxylate