Asymmetric synthesis of (1'S,2'R)-cyclopropyl carbocyclic nucleosides

Article abstract of DOI:10.1021/jo00121a047

Enantiomeric synthesis of cyclopropyl carbocyclic nucleosides has been accomplished. The key intermediates 7 and 9 were synthesized from D- glyceraldehyde acetonide 1, which was converted to the α,β-unsaturated ester 2 and then reduced to give allylic alcohol 3a. Stereoselective construction of the cyclopropyl ring of 3a and 3b followed by oxidation gave acid 5, which was treated under Curtius rearrangement conditions to obtain the urea intermediate 7. The urea intermediate was utilized to prepare uracil 14, thymine 15, and cytosine 18 nucleosides. The purine derivatives were prepared from cyclopropylamine 9 by condensation with 4,6-dichloro-5-form- amidopyrimidine or 4,6-dichloro-2-aminopyrimidine.