Synthesis of 2′‐ and 3′‐C‐Methylribonucleosides

Abstract

A simple, efficient method for the synthesis of 2'- and 3'-C-methylribonucleosides starting from a common precursor is described. This synthesis achieves conversion of 1,2:5,6-di-O-isopropylidene-3-C-methyl-alpha-D-allofuranose into 1,2,3-tri-O-acetyl-5-O-benzoyl-3-C-methyl-alpha,beta-D-ribofuranose followed by condensation with nucleic acid bases, with a final ammonolysis leading to 3'-C-methylribonucleosides. Alternatively, the same branched allofuranose converted to l,2,3-tri-O-acetyl-5-O-p-methylbenzoyl-2-C-methyl-beta-D-ribofuranose, after analogous Vorbruggen condensation and ammonolysis, provides 2'-C-methylribonucleosides.