An expeditious synthesis of 3′-α-carboxymethyl-2′-O-methyl ribonucleosides

Abstract 3′-α-Carboxymethyl-2′-O-methyl ribonucleosides, which are important building blocks for the construction of high affinity amide modified antisense oligonucleotides, have been synthesized from the corresponding 2′-O-methyl ribonucleosides via catalytic hydrogenation of their 3′-deoxy 3′-methoxycarbonyl-methylidene derivatives. Reduction of the olefinic double bond proceeds in good to excellent yields and with α/β-product ratios > 9/1.