Lithiation of a protected methyl 2-chloro-l-(β-D-ribofuranosyl) imidazole-4-carboxylate with LDA affords the C-5 anion which reacts with a wide range of electrophiles to provide various types of 5-substituted derivatives. Application of this method to the synthesis of 3- deazaguanosine, an antiviral nucleoside, is also described.
