(3S,4R,5S)-3-Amino-4,5-dihydroxycyclopentene, the cyclopentene segment of queuosine found in the first position of the anticodon of +RNA,Tyr +RNA,His +RNA,Asn and +RNA,Asp has been synthesized in a stereoselective manner from (-)-3-endo-hydroxydicyclopentadiene.