Synthesis of 5′-alkylthio-5′-deoxynucleosides from nucleosides in a one-pot reaction

5′-Alkyl (aryl) thio-5′-deoxynucleosides [alkyl (aryl) nucleoside sulphides] were prepared in high yields by the reaction of nucleosides with dialkyl or diaryl disulphides in the presence of tri-n-butylphosphine. The method is widely applicable to the synthesis of unsymmetrical sulphides.