(1'S,4'R)-9-[4-(tert-butoxymethyl)cyclopent-2-enyl]-6-chloropurine

Benzoic acid (3aR,4R,6S,6aS)-6-tert-butoxymethyl-2-methoxy-tetrahydro-cyclopenta[1,3]dioxol-4-yl ester

(-)-[(1R,4S)-tert-butyl 3-oxo-2-azabicyclo(2.2.1)hept-5-ene-2-carboxylate]

(1S,cis)-tert-butyl N-[4-(hydroxymethyl)-2-cyclopenten-1-yl]carbamate