L-(1'S,3'S)-9-[3-Fluoro-3-(hydroxymethyl)cyclopentan-1-yl]adenine 15 has be
en synthesized from ester 2, which can be conveniently prepared from 2,3-is
opropylidene-D-glyceraldehyde 1 in six steps. The key ring closure has been
accomplished through an intramolecular nucleophilic substitution reaction.