(R)-2,4-Dihydroxybutyramide seco-Pseudonucleosides: New Versatile Homochiral Synthons for Synthesis of Modified Oligonucleotides

Abstract
Two series of seco-pseudonucleoside synthons were synthesized from (R)-(+)-α-hydroxy-γ-butyrolactone and (R)-(−)-pantolactone by aminolysis, side-chain protection, dimethoxytritylation, and phosphitylation or solid-phase attachment. The phosphoramidites and solid supports were used in automated DNA synthesis to prepare oligonucleotides modified with one or more 2,4-dihydroxybutyramide units bearing side-chain reporter groups. These new oligonucleotide modification reagents allow the introduction of a label into any desired position within an oligonucleotide chain during solid-phase assembly.