A cost-effective process scale method for preparing purine dioxolane nucleoside derivatives in racemic or optically pure form is disclosed, as are nucleoside derivatives prepared by the method. The method involves reacting a purine or a mono- or polysilylated purine derivative with an activated dioxolane analog to produce the dioxolane nucleoside analog in commercially useful yields. Direct reaction of purine or a mono- or polysilylated purine with dioxolanes takes place with highest reported chemical yields and excellent stereoselectivity when an additive in the form of an alpha cyano carbonyl compound or silylated alpha cyano carbonyl compounds is present in the reaction mixture during the glycosylation reaction.
