N-Glycosylation with Sulfoxide Donors for the Synthesis of Peptidonucleosides

We report here the synthesis of peptidonucleosides obtained after glycosylation of different pyrimidine bases with glucopyranosyl donors carrying an azide group at the C4 position. A methodological study involving different anomeric leaving groups (acetate, phenylsulfoxide and ortho -hexynylbenzoate) showed that a sulfoxide donor in combination with trimethylsilyl triflate as the promoter led to the best yields.