Stereocontrolled lactonisation of gamma,delta-epoxy beta-hydroxyesters
provides, after reduction, 2-deoxysugars in pyrano or furano form. Af
ter appropriate protections of the hydroxyl functions, these sugars ca
n be converted to various 2'-deoxynucleosides with different configura
tion of the sugar moiety and an extra functionalisation at C-5.