Rapid access to 2'-branched-carbocyclic nucleosides and their 4'-epimers from 2-alkyl-cyclopentene-1-ones.

2-Methyl-2-cyclopentene-1-one was used as starting material in a novel route toward 2'-branchedcarbocyclic nucleosides. This methodology was efficiently adapted to the preparation of 4'-epicarbocycles. A series of this new class of molecules was synthesized as potential antiviral compounds.