(3aR,6aR)-3a,6a-dihydro-2H-cyclopenta[b]furan-2,6(3H)-dione

(1R,2R,3R)-1,2-dihydroxy-3-(2-hydroxyethyl)cyclopent-4-ene

(1R,5R,6R,7R,8S)-6,7-Epoxy-8-hydroxy-2-oxabicyclo[3.3.0]octan-3-one

(1S,2R,3S,4S,5S)-1,2-isopropylidene-4-benzylamino-5-(2-hydroxyethyl)-1,2,3-cyclopentanetriol

(1S,2S,3S,4S,5S)-4-N-benzyl-5-acetoxymethyl-7,8-isopropylidenedioxy-2-oxa-4-azabicyclo[3.3.0]oct-3-one