benzyl (R)-2-((R)-1,4-dihydroxybutyl)pyrrolidine-1-carboxylate

benzyl (R)-2-((S)-1,4-dioxaspiro[4.5]decan-2-yl)pyrrolidine-1-carboxylate

(R)-1-benzyloxycarbonyl-2-[(S)-1,2-dihydroxyethyl]pyrrolidine