Synthesis of 2′,3′-dideoxynucleosides via C-S bond cleavage: N-glycosylation of 2,3-dideoxy-1-[(2-pyridylmethyl)thio]glycoside

N-Glycosylation of 2,3-dideoxy-1-[(2-pyridylmethyl)thio]glycosides (1a) using several activators is described. NBS-promoted glycosylation reaction utilizing either the α- or β-thiodideoxyglycoside proceeded smoothly at −78 °C to give the corresponding dideoxynucleoside in a β-selective manner, presumably through a common glycosyl donor.