ENANTIOMERIC SYNTHESIS OF 3'-FLUORO-APIONUCLEOSIDES USING CLAISEN REARRANGEMENT

Enantiomeric synthesis of 3'-fluoro-apionucleosides was accomplished f rom 1,2-O-isopropylidene D-glyceraldehyde. The key intermediate, gamma ,beta-unsaturated tert-fluoro ethyl ester 7 from the fluoro allylic al cohol derivative 5 was achieved via Claisen rearrangement reaction wit h a 90.4% enantioselectivity. The condensation of the intermediate 10 with silylated N-4-benzoylcytosine and 6-chloropurine followed by depr otection gave the desired pyrimidine and purine apionucleosides, respe ctively. (C) 1998 Elsevier Science Ltd. All rights reserved.